Challenges, critical factors and interrelated improvement measures in sustainable online grocery retailing: insights from the German e-grocery market Open Access

The rapid expansion of e-commerce has significantly transformed the global retail sector, particularly the grocery industry (Rodríguez-García et al., 2023). Driven by advancements in digital technologies, increased Internet accessibility and evolving consumer behaviors, online grocery sales have expanded significantly (Argyropoulou et al., 2023; Schnieder et al., 2023). By 2028, the global grocery market is projected to grow by USD 456.6 billion, with e-commerce identified as a primary driver (Technavio, 2024). Although online grocery sales currently represent a relatively small share of the German market, their anticipated growth underscores the strategic importance of this segment (Ehrler et al., 2021).

However, this growth presents significant logistical challenges, particularly regarding sustainability. In supply chain management, sustainability is typically understood through the Triple Bottom Line (TBL) framework, which considers three key areas: economic viability, ecological responsibility and social equity (Elkington, 1997).

Economically, ensuring supply chain efficiency and resilience remains critical to meeting growing consumer demands while maintaining profitability (Schnieder et al., 2023). Ecologically, the rise in online grocery shopping has increased food and packaging waste and heightened CO₂ emissions due to expanded delivery logistics (Zhang et al., 2022). Socially, issues such as delivery accuracy, safety and the tension between consumer convenience and community well-being remain critical concerns (Li et al., 2023).

The three sustainability dimensions (economic, ecological and social) are inherently interconnected and should not be addressed in isolation. Integrating them is essential to avoid optimizing one goal at the expense of others. This integrated approach is particularly critical in logistics-intensive sectors such as online grocery retailing, where operational choices frequently generate trade-offs and synergies across the dimensions. For instance, narrow delivery windows may enhance customer satisfaction (social goal) but demand more frequent journeys with vehicles that are not fully utilized, thus increasing travel distances (economic goal) and emissions (ecological goal) (Fikar, 2018).

Existing research often treats these issues independently, neglecting the systemic interdependencies across supply chain stages (Heikkinen, 2024). Previous studies prioritize specific dimensions, without fully exploring how cross-dimensional measures could yield more balanced and sustainable outcomes (Fikar, 2018). The literature often prioritizes cost-efficient logistics (Calzavara et al., 2023; Rodríguez-García et al., 2023; Wollenburg et al., 2018) or carbon emission reduction (Motte-Baumvol et al., 2023; Siragusa and Tumino, 2022), yet fails to comprehensively analyze how logistical challenges interact and influence one another (Akkerman et al., 2010; Winkler et al., 2023).

This lack of integration creates a significant knowledge gap. A comprehensive understanding is needed to develop improvement measures that align sustainability goals across the TBL dimensions (Li et al., 2023). Ultimately, integrating economic, ecological and social sustainability within online grocery logistics is essential for developing a sustainable online grocery model that balances operational efficiency with ecological and social considerations (Toniolo et al., 2024).

This paper addresses these shortcomings by examining logistical challenges that impede the development of sustainable business models in the German online grocery market. The aim of the study is to identify the critical factors that are necessary for a sustainable online grocery business. In particular, this study will recommend measures to interrelate and improve the critical factors identified for economic, ecological and social sustainability. Finally, the factors with the greatest potential to improve sustainability across the three dimensions and those most receptive to improvement will be identified. Areas of focus include optimizing warehouse and delivery logistics to minimize environmental impacts, adopting innovative packaging solutions and measures to reduce waste and designing supply chains to enhance customer satisfaction and long-term value creation (Collins, 2023; Gruntkowski and Martinez, 2022; Valuer, 2022).

This paper comprehensively investigates embedding sustainability into online grocery supply chain management by synthesizing findings from existing research and recommending improvement measures. It contributes to academic discourse and provides practical insights for industry stakeholders seeking to drive sustainability in the rapidly evolving online grocery sector.

Online grocery retailing (OGR) is a rapidly evolving segment of e-commerce where grocery retailers use digital platforms to deliver grocery products directly to consumers (Martín et al., 2019). Unlike other e-commerce sectors, OGR faces unique challenges, including large order sizes (60–80 items per basket), multi-temperature storage and the non-returnability of fresh products (Hübner et al., 2019). Additionally, consumers are less willing to pay premium prices for online groceries than for in-store purchases, making cost optimization essential (Fikar et al., 2021).

At the same time, achieving sustainable online grocery retailing (SOGR) remains complex (Li et al., 2020), given the need to balance economic, ecological and social sustainability – the three dimensions of the TBL (Elkington, 1997). A growing body of research has explored these dimensions. However, as summarized in Table 1, the literature remains fragmented and exhibits important gaps.

Economic sustainability is the most widely studied dimension of SOGR research, reflecting the sector's intense pressure and low margins. Studies in this domain examine areas where costs and delivery times can be reduced without compromising service quality.

For example, Agatz et al. (2011) demonstrate how narrow time slots in home delivery increase logistics costs by up to 25%, while flexible or regional differentiated time slots reduce costs by 10% through better route optimization. Comparing fulfillment models, Rodríguez-García et al. (2023) find that store-based models incur higher picking costs, while warehouse models face higher delivery costs.

A critical area of research in economic sustainability is the integration of omnichannel logistics, which seeks to balance online and offline operations. Wollenburg et al. (2018) emphasize that warehousing and transportation strategies must be adapted effectively to balance in-store and e-commerce demand. Building on this, Seidel (2021) classifies service models according to storage, picking and distribution costs and provides benchmarks for choosing between home delivery and order collection. Integrating both channels, Hübner et al. (2016) propose a strategic framework with back-end fulfillment and last-mile distribution concepts, noting the importance of tailoring solutions to country-, customer- and retailer-specific factors. Similarly, Marchet et al. (2018) propose a comprehensive omnichannel strategy that incorporates delivery service, distribution setting and returns management tailored to the retailer's maturity level. Extending this work, Calzavara et al. (2023) develop a cost-based decision support system for optimizing warehouse location, picking strategies and transport, improving overall network efficiency.

More recent research has increasingly focused on fulfillment design and value-creation archetypes in SOGR. Auf Der Landwehr et al. (2024) highlight that fulfillment performance depends on both order management (inventory handling and order preparation) and delivery management (delivery planning, delivery operations and returns). Their study identifies six archetypes that reflect different strategic orientations for economic value creation in SOGR.

Beyond operational strategies, innovative business models have also been proposed to improve economic outcomes. For instance, Belavina et al. (2017) and Wagner et al. (2021) examine subscription models, which improve inventory turnover and revenue but may also increase delivery frequency and emissions. Li et al. (2023) provide additional insights, revealing that lowering the threshold for free shipping encourages larger orders, whereas reducing flat-rate fees discourages them. Collaboration between retailers offers another promising avenue to improve efficiency and reduce costs. Serrano-Hernandez et al. (2020) and Zissis et al. (2018) demonstrate that horizontal cooperation reduces delivery distances and lead times while enhancing service quality.

Emerging work on crowdshipping further expands the spectrum of economically oriented innovations. De Oliveira Leite Nascimento et al. (2025) show that leveraging customers as crowdshippers can substantially decrease vehicle kilometers driven and improve delivery efficiency. In their study, home delivery customers serve as receivers and click-and-pick or in-store shoppers act as deliverers. The greatest reductions occur when customers take small detours to deliver to end-users, indicating significant potential for low-cost, high-flexibility last-mile solutions.

Technological innovations have also contributed to economic sustainability. Mkansi et al. (2020) note that mobile applications have a transformative impact on distribution efficiency by aggregating demand and optimizing delivery routes, particularly in urban areas. Completing this, Mkansi and Nsakanda (2025) examine e-grocery adoption challenges from the technological, organizational and environmental perspectives. They find that organizational barriers remain the dominant constraint. This result suggests that economic efficiency gains are increasingly dependent on firms' internal capabilities to implement and scale innovations rather than technological availability.

Although ecological sustainability has gained increasing attention in recent years, it has not been examined as thoroughly as economic aspects. In SOGR, ecological sustainability primarily focuses on minimizing food and packaging waste and reducing carbon emissions.

Food waste is a critical issue in SOGR. Fikar (2018) proposes a “first-expired, first-out” picking model to reduce spoilage, while Belavina et al. (2017) suggest that smaller, more frequent purchases (via subscriptions) can reduce household food waste but increase transport emissions. Recent research provides further insight into systemic causes of food waste across the e-commerce food supply chain. Mohammed et al. (2025a) show that ineffective storage, insufficient demand forecasting leading to overstocking and improper packaging are key drivers of food waste. The study identified consumers, suppliers and retailers as significant contributors. Complementing this, Mohammed et al. (2025b) confirm that consumers remain the dominant source of waste, followed by suppliers and online retailers and highlight improper packaging as a major cause from the consumer point of view. The authors further emphasize that food waste mitigation requires integrated collaboration across supply chain partners and interorganizational coordination, suggesting that ecological sustainability must be addressed collectively rather than solely within individual retail practices.

Packaging waste in SOGR is another concern. Zhang et al. (2022) report that packaging accounts for 32% of delivery-related waste, with white-collar customers producing more than other customer segments. The findings of Mohammed et al. (2025a, b) reinforce this issue by identifying improper packaging practices not only as a contributor to waste generation but also a factor exacerbating product spoilage, thereby linking packaging directly to both waste volume and food quality deterioration.

Several studies quantify the carbon footprint of SOGR. Siragusa and Tumino (2022) report that warehousing can contribute up to 60% of emissions in online grocery systems. However, larger basket sizes can mitigate this impact by reducing delivery frequency, making OGR 10–30% more sustainable than conventional shopping. Similarly, Motte-Baumvol et al. (2023) highlight that households using online grocery services reduce their emissions by 37% due to fewer physical store visits. Nevertheless, Heldt et al. (2021) note that the potential of home delivery to reduce emissions depends on the refrigeration needs for perishable goods. In hotter climates, cooling requirements can significantly increase fuel consumption and emissions.

Distribution models also influence emissions. Durand and Gonzalez-Féliu (2012) find that depot picking combined with out-of-home delivery reduces CO₂ emissions more effectively than other methods, although it is more costly and time-consuming. Similarly, Schnieder et al. (2023) propose using railway stations as local distribution hubs to reduce environmental impacts significantly. Complementing these approaches, research on sustainable routing highlights the potential of alternative vehicle technologies. Prencipe et al. (2024) demonstrate that electric cargo bikes and e-mopeds can reduce total service time for deliveries in dense or restricted urban areas, such as historic districts or zones with traffic and parking limitations. Tudisco et al. (2025) extend this perspective by incorporating on-demand third-party logistics providers into routing models. They demonstrate that prioritizing environmental objectives can reduce emissions by over 90%, with only marginal increases in annual costs. Their findings show that flexible, on-demand vehicle use allows companies to adopt sustainable delivery solutions without requiring major upfront investment in a dedicated fleet.

Emerging technologies, such as electric vehicles and autonomous delivery systems, promise significant ecological benefits. However, these advancements are encumbered by challenges concerning infrastructural limitations and operational complexity (Ehrler et al., 2021; Figliozzi, 2020). The addition of flexible electronic micro-mobility solutions (Prencipe et al., 2024) and hybrid human-3PL routing systems (Tudisco et al., 2025) suggests that future development in ecological sustainability will rely on combining technological innovation with context-sensitive, adaptive routing strategies.

Social sustainability, focusing on accessibility, equity, worker well-being and customer satisfaction, remains the least developed dimension in SOGR literature.

Studies exploring this dimension highlight the persistent trade-offs between meeting customer expectations and maintaining operational efficiency. Fikar et al. (2021) note that tight delivery windows and extended shelf-life guarantees appeal to customers but reduce vehicle utilization and delivery efficiency. Similarly, Li et al. (2018) argue that flexible order cancellation attracts demand but can hurt profitability if orders are not priced carefully.

Improving delivery success rates also enhances customer satisfaction. Pan et al. (2017) demonstrate that predicting customer presence using household energy consumption data can improve delivery success rates by 18%–26% and reduce travel distances by 3%–20%. Alternative pick-up points can likewise strengthen accessibility. Vyt et al. (2017) show that grocery pick-up systems create regional value and reduce delivery lead times, offering a valuable alternative to traditional home delivery.

Collaboration between retailers also generates social benefits. Serrano-Hernandez et al. (2020) report that horizontal cooperation can improve service quality by up to 29% and reduce lead times by 39%, fostering a customer-centric supply chain.

Beyond customer-facing aspects, social sustainability is increasingly encompassing the experiences and well-being of delivery workers, whose roles are essential yet often undervalued. Recent studies have raised concerns regarding safety and fairness. Kavta et al. (2025) investigate delivery drivers' routing decisions and find that safety information and monetary incentives can encourage riders to choose safer, albeit longer, routes to reduce crash risks. Ko et al. (2025) further reveal that drivers frequently perceive their working conditions as unequal and unfair, citing insufficient resources to maintain the required safety standards. Addressing these issues requires active communication and information-sharing among all stakeholders, emphasizing the need for inclusive and supportive organizational practices.

Internal labor conditions within e-grocery operations also influence social sustainability. Saydam et al. (2024), analyzing employee reviews, identify positive aspects such as the company environment, salary and cultural values. However, they also note dissatisfaction related to work-life balance and perceptions of favoritism. These findings resonate with those of Sharma (2025), who examines reworking and resilience strategies that frontline employees develop to cope with workplace challenges. The study shows that, rather than relying on resilience strategies such as adjusting their mindset, workers rely more on reworking practices, i.e. adjusting tasks and workflows. This insight highlights the importance of organizational support structures that can reduce the burden on employees of having to self-manage difficult working conditions.

Social sustainability also extends to broader participation in digitally enabled service ecosystems. Vu et al. (2025) find that in sharing-economy delivery settings, individuals' willingness to participate as service providers is positively influenced by perceived social and economic benefits, as well as by the corporate image of the enabling platform. The study shows that reputational factors play a key role in establishing trust and perceived fairness, elements central to socially sustainable online grocery operations.

Finally, Hübner et al. (2019) and Larke et al. (2018) emphasize the importance of adapting service designs and organizational practices to local cultural and institutional contexts to ensure accessible, equitable and socially acceptable service delivery.

Despite the progress documented above, several critical gaps in the literature remain. Most notably, many studies address the distinctive sustainability dimensions in isolation, overlooking their interdependencies and trade-offs (Akkerman et al., 2010). Only Fikar (2018), Zissis et al. (2018) and Krishna et al. (2025) consider all three dimensions simultaneously, albeit with a specific focus on distribution. Researchers, therefore, call for investigations that quantify synergies and trade-offs between the sustainability dimensions to support more effective decision-making in SOGR (Toniolo et al., 2024).

Moreover, while economic sustainability dominates current research, the social dimension remains underexplored (Li et al., 2023). Likewise, ecological aspects beyond CO₂ emissions, such as cold chain sustainability and packaging innovations, require deeper investigation (Winkler et al., 2023). Recent work reinforces this need. Mohammed et al. (2025b) highlight that future research should expand to include all TBP dimensions, especially the social dimension.

Most existing studies emphasize last-mile delivery, leaving upstream processes such as warehousing, inventory management and reverse logistics largely unexplored (Siragusaand Tumino, 2022). Future research should, therefore, explore how these logistical components interact and jointly contribute to SOGR (Winkler et al., 2023). Auf Der Landwehr et al. (2024) call for a more holistic understanding of fulfillment in e-grocery, emphasizing that research must move beyond isolated operational tasks and instead adopt an integrated view of SOGR.

Current research also tends to focus narrowly on technological innovations, consumer preferences or logistics network design (Lagorio and Pinto, 2021). This focus has resulted in a limited exploration of the logistical challenges of SOGR in terms of economic, ecological and social sustainability. The interrelationships among these challenges remain unclear, as emphasized by Marchet et al. (2018). Building on this critique, Calza et al. (2023) note that the broader online food delivery ecosystem remains insufficiently understood.

Comparative studies between home delivery and click-and-collect remain scarce, even though both models share similar logistical and sustainability challenges (Hübner et al., 2016; Motte-Baumvol et al., 2023; Siragusa and Tumino, 2022). Future research should therefore explore the competitive dynamics between pure online and omnichannel models and assess their implications for sustainability (Belavina et al., 2017; Larke et al., 2018).

Finally, empirical and qualitative studies remain limited (Ehrler et al., 2021; Jones et al., 2022; Kembro et al., 2018; Mangiaracina et al., 2015; Marchet et al., 2018), as does research focused specifically on the German online grocery market, where consumers exhibit high price sensitivity alongside strong environmental awareness (Hübner et al., 2016).

To address these research gaps, this study aims to comprehensively understand how economic, ecological and social factors interrelate in SOGR. This comprehensive examination will enable the development of recommended measures for online grocery retailers seeking to improve their sustainability performance. Accordingly, we propose the following research questions to guide our investigations:

This study investigates the sustainability challenges and critical factors in SOGR from retailers' perspectives, with a particular focus on logistical challenges inherent in SOGR. The research was motivated by gaps identified in the existing literature, which tends to examine economic, ecological and social sustainability dimensions in isolation. To address this fragmentation, our study aims to explore the interrelationships among these dimensions and to identify measures that improve SOGR logistics in a more integrated manner.

Following the research onion framework (Saunders et al., 2023), this study adopts an interpretivist philosophy, which assumes that sustainability challenges and practices are socially constructed and shaped by the experiences, perceptions and interpretations of practitioners.

In line with this philosophy, the study follows an abductive approach to theory development. Abduction allows empirical observations to be systematically compared with existing theory in an iterative process, enabling the refinement, extension or reconfiguration of theoretical understanding (Saunders et al., 2023). In this study, initial insights from the literature informed the research focus and interview design, while emerging empirical patterns were subsequently interpreted and integrated with established sustainability and logistics concepts to develop interconnected and empirically grounded measures for SOGR.

The methodological choice is a qualitative research design, which is particularly appropriate for investigating complex, interrelated and underexplored phenomena. Qualitative methods enable in-depth exploration of how practitioners experience, interpret and manage sustainability challenges, which is essential for understanding the trade-offs and operational realities of SOGR (Trautrims et al., 2012).

The research strategy is based on Grounded Theory (Binder and Edwards, 2010). Grounded Theory was specifically chosen because it enables the discovery of patterns and interrelationships among sustainability challenges directly from empirical data rather than from predefined hypotheses (Oláh et al., 2018). Consistent with the logic of abductive Grounded Theory, data collection and analysis were conducted iteratively, with emerging insights shaping and being tested in subsequent interviews (Corbin and Strauss, 1990). To capture diverse operational contexts, the study includes two types of retailers:

1. Pure online grocery retailers that operate exclusively through e-commerce platforms and rely solely on home delivery fulfillment strategies.

2. Omnichannel grocery retailers that sell groceries online and in physical stores utilize a mixed strategy that combines home delivery and click-and-collect services.

Companies and participants were selected according to several criteria to ensure a range of diverse and informative perspectives. We targeted participants in different leading positions within each company to capture varied viewpoints on sustainability challenges, practices and future visions. We also included participants with different levels of work experience to identify not only mature solutions but also challenges that emerge in earlier stages of SOGR. Among omnichannel retailers, we sought variation in the proportion of online sales relative to total sales to reflect different levels of e-commerce integration. Finally, we included companies with different experiences in the online grocery market for different lengths of time, enabling us to address challenges encountered at the initial and later stages of online grocery development. This purposeful sampling strategy ensured a rich and balanced understanding of sustainability challenges across organizational contexts. Table 2 provides an overview of the participants and their respective companies.

Data were collected in two stages. First, a review of academic literature, industry reports, company sustainability disclosures and relevant statistics was conducted to understand current sustainability initiatives and identify initial topics for exploration. Importantly, this review served as contextual background, not as part of theory building, to remain consistent with Grounded Theory's inductive orientation (Glaser and Strauss, 1999). Accordingly, this study follows a Straussian grounded theory approach, which allows prior literature to be used sensitively for contextualization and theoretical positioning without constraining inductive category development (Corbin and Strauss, 1990).

Second, primary data were gathered through fourteen semi-structured interviews with managers and decision-makers in German grocery companies. Interviews were chosen as the primary data collection method because they allow for deep, nuanced insights into practices and challenges (Creswell and Creswell, 2018).

The interview guide was structured into two sections (see  Appendix 1). The first section addressed organizational background and online sales operations, while the second section focused on sustainability challenges and recommended measures to address them across each dimension of the TBL. Sample interview questions explored key logistical challenges, trade-offs between sustainability objectives and specific improvement measures that had been implemented or were planned by the company. In line with Grounded Theory's emphasis on openness to emerging themes, the guide was intentionally broad, while still ensuring systematic coverage of all three TBL dimensions and the four research questions. Although the interview guide provided a structured reference point, the wording and sequencing of questions were flexibly adapted during the interviews to allow for deeper exploration of emergent themes (Manuj and Pohlen, 2012).

A pilot interview with a grocery retail employee was conducted to test the interview guide, resulting in minor wording and thematic focus refinements. Given the geographical dispersion of participants, all interviews were conducted online in late 2023 and lasted on average 63 min each.

Following Grounded Theory principles (Corbin and Strauss, 1990), data collection and analysis proceeded iteratively. Each interview was coded immediately upon completion, with preliminary findings determining the focus and questions in subsequent interviews. This iterative process enabled the researchers to explore emerging patterns and test evolving insights as the data collection progressed.

Theoretical saturation was used to determine the final number of interviews. To assess theoretical saturation systematically, we tracked the emergence of new themes throughout the data collection process. In the initial round of interviews (OCR1, OCR3, OCR6, ER1, ER2 and ER3), 17 base themes were identified. In subsequent iterations, the number of new themes identified decreased steadily. After the fifth iteration, no new themes emerged, indicating that theoretical saturation had been achieved. Consistent with established criteria for saturation (Glaser and Strauss, 1999), this pattern demonstrates that collecting more data only confirmed existing categories and did not generate new insights. Triangulation was applied across researchers to enhance validity. Therefore, the authors collaborated to develop the interview guide, observe selected interviews and discuss emerging findings to minimize individual bias.

Data analysis followed the Grounded Theory procedures outlined by Gioia et al. (2013). These procedures operationalized the classic coding steps of first-order concepts, second-order themes and aggregated dimensions. All interviews were transcribed verbatim and analyzed systematically using MAXQDA 24 software.

During the open coding phase, key statements from the participants were extracted and grouped into first-order concepts, which largely reflect the respondents' own words. These 19 first-order concepts represent the specific sustainability-related problems or obstacles experienced by retailers, which we refer to as sustainability challenges. These challenges were clustered into seven second-order themes in the axial coding phase. These factors capture patterns across individual challenges and represent the critical factors in SOGR. The seven second-order factors were aggregated into the three overarching dimensions in the final theoretical integration phase, aligned with the TBL framework. As a result, the seven identified critical sustainability factors, which were grouped into the three TBL dimensions, were organized within an active-passive matrix. In this matrix, each factor was classified as active, meaning it drives sustainability and passive, meaning other factors influence it.

In a subsequent step, each interview was analyzed again to extract the measures recommended by participants to address the identified sustainability challenges and improve the critical factors in SOGR. These recommendations were selected to illustrate improvement measures capable of simultaneously mitigating at least two critical sustainability factors. Finally, the total impact strength of each factor within the matrix was evaluated by counting how many other factors it positively influences. This procedure helped to identify the factors with the greatest impact on promoting SOGR. Similarly, each factor was assessed for its potential to be influenced by others to identify those most receptive to improvement.

To ensure the quality and credibility of the coding, two researchers independently coded each transcript, then compared their results to assess inter-coder reliability and resolve any discrepancies through discussions. A detailed overview of the coding hierarchy and results is provided in  Appendix 2.

This section addresses the first two research questions (RQ1 and RQ2) by exploring the sustainability challenges online grocery retailers face and identifying critical factors in SOGR. The analysis is structured around the three dimensions of the TBL: economic, ecological and social sustainability.

Interview participants described several operational challenges affecting efficiency and profitability in OGR. We identified three critical factors in the economic dimension: storage, picking and last-mile transportation.

Although retailers highlighted effective storage as a critical factor for sustainable operations, challenges in updating inventory and ensuring adequate storage capacity persist.

Experts reported inaccurate inventory data when stock systems fail to reflect supplier shortages (ER4), outdated assortments (ER5) or expired products (OCR7). Participants also reported reliance on manual stock adjustments, which were described as both time-consuming and error-prone (OCR3, ER6). According to OCR5, regional differences in warehouse operations can create inconsistencies in product availability between locations, exacerbating the problem.

In omnichannel settings, integrating online and physical retail operations presents additional problems. Missing sales rights or incomplete product information for online listings (OCR4) leads to compliance issues and lost sales opportunities. Additionally, the lack of real-time synchronization between online and physical stores leads to discrepancies between online stock levels and in-store availability, resulting in unfulfilled orders and customer dissatisfaction (OCR2 and OCR4). These issues are further compounded by the limited storage capacity of physical stores, which can lead to trade-offs between meeting online demand and maintaining sufficient inventory for in-store customers, ultimately leading to unfulfilled orders in both channels (OCR7).

Interview participants identified order picking as another critical factor for sustainable retail operations. Several challenges undermine its effectiveness, notably defective picking practices and long picking times.

Defective picking practices are primarily due to human errors, such as inaccuracies in item quantities (ER2) caused by manual scanning (ER7). Additional issues include placing items in incorrect boxes (ER2) and overlooking product quality during picking, as OCR5 highlights:

Inadequate handling of sensitive products further exacerbates these problems, often resulting in damage, waste and increased retail costs (ER7).

The issue of long picking times is attributed to the lack of automation and the dependence on manually determined picking routes, which results in sub-optimal paths and significant delays (OCR1, OCR4, OCR5 and ER2). These delays are further aggravated by time-consuming manual product scanning during picking (ER7) and the additional effort required to locate replacement products for out-of-stock items (OCR4 and ER6). Issues such as non-standardized shelf locations (OCR4 and ER6) and poor store layouts (OCR2, OCR4 and ER7) intensify delays.

In omnichannel retailing, the absence of a predefined picking sequence also hampers efficiency by requiring employees to rearrange shopping baskets mid-process to prevent damage to sensitive products (OCR2). Participants reported that order picking during regular store hours exacerbates delays caused by interruptions from in-store customers, slowing down the process and increasing error rates (OCR2, OCR4, OCR6 and OCR7). These disruptions are intensified by long check-out waiting times, further delaying order fulfillment and extending overall picking time (OCR4).

In the context of SOGR logistics, retailers have identified a number of challenges related to last-mile distribution, which is the third critical factor. These challenges are associated with logistics service providers, product cooling, delivery vehicles, transport capacity and delivery area.

Retailers who rely on third-party logistics providers face several issues that affect delivery quality. Theft and loss of parcels in transit are ongoing concerns, resulting in financial losses and eroding customer trust (ER2 and ER3). Moreover, these providers' rough handling of products often results in damaged goods.

Furthermore, quality control is often lacking at the delivery stage, as the condition and quality of goods are not reassessed before reaching the customer (OCR4, OCR5 and ER2).

Maintaining the correct temperatures during transportation is another challenge, particularly for perishable goods. Refrigeration units in delivery vehicles often fail in extreme heat (ER1, ER2, ER5 and ER7), resulting in spoilage, especially on long journeys (ER7) or when undelivered orders remain in vehicles (OCR7 and ER3). While dry ice is sometimes necessary, it poses supply challenges, especially during peak periods such as the COVID-19 pandemic (ER5). Furthermore, separating temperature-sensitive items from those that should not be refrigerated increases packaging complexity and costs (OCR5, ER3, ER5 and ER6). As ER1 notes:

According to participants, the characteristics of delivery vehicles further complicate the establishment of SOGR. Conventional vehicles face challenges due to fluctuating fuel prices and the high CO₂ emissions they produce, which are particularly problematic in urban areas (OCR2 and OCR4). Electric vehicles, as an alternative, are not without their own limitations. These include dependence on public charging infrastructure (OCR6), limited availability of charging stations (ER2) and limited driving ranges (ER5), which may not be sufficient for longer distances.

Transportation capacity also complicates delivery operations. Smaller vehicles, such as bicycles or mopeds, often lack sufficient space, making them inefficient for widespread deliveries (OCR7 and ER6). Conversely, larger vehicles may be underutilized in low-demand areas, resulting in inefficient use of resources and higher operating costs (OCR5, ER2 and ER4). Moreover, product-specific packaging requirements add complexity. Some items must be separated from others to prevent contamination, resulting in multiple boxes that are not fully utilized (OCR5, ER3 and ER6). As ER5 explains:

Deliveries in urban environments pose unique delivery challenges due to heavy traffic, narrow streets and limited parking, which increase delivery times and effort (OCR2, OCR4, OCR6, ER2 and ER6). Logistics are further complicated in areas with multi-story blocks or flats (OCR2 and ER4).

Conversely, rural areas face inefficiencies such as low customer density and widely dispersed delivery points. This results in lengthy routes that consume significant time and resources in the delivery process (OCR2, OCR4, OCR5, ER1, ER2 and ER6). In this context, efficiently clustering customers becomes a complex task.

Interview participants reported several challenges in reducing waste and minimizing resource use. The main factors identified in the ecological dimension include food waste and food packaging.

In SOGR, experts identified food waste as a critical factor in achieving ecological sustainability, driven by challenges in product handling and quality control, shelf-life management and customer behavior.

A significant cause of food waste is improper handling and poor-quality control throughout the supply chain. Mishandling by suppliers, such as pallets tipping over during transit, can render entire shipments unusable (ER5). Sensitive items are particularly vulnerable to damage.

Maintaining an unbroken cold chain is essential for food quality and safety, but disruptions during transit or storage often lead to spoilage (ER1 and ER2). Failures in refrigeration units further shorten the shelf life of perishable goods, exacerbating waste (ER1, ER2, ER5 and ER7). Regulatory restrictions complicate the situation by prohibiting the return of fresh groceries due to potential cold chain breaches, preventing retailers from reintegrating returned items into their inventory (OCR2, OCR4, OCR5, OCR7, ER2 and ER3).

Another challenge that exacerbates food waste is the shelf life of products. Suppliers often deliver mixed batches of products, some with low demand, leading to excess inventory that cannot be sold. As ER5 describes:

In this context, goods with short best-before dates give retailers limited time to sell products before they expire (ER3). Items delivered with expired, unclear or missing expiration labels, such as herbs, fruits, vegetables and bread, add further complexity (OCR4, OCR6, OCR7, ER3 and ER7).

Food waste is also driven by customer behavior, as the variability in customer orders increases the risk of overstocking and incorrect picking, which can result in additional food waste in the worst case (ER2 and ER3). Unwanted substitute products further exacerbate this issue, as customers often reject replacements that do not meet their expectations (OCR5, OCR7 and ER2). Moreover, differing preferences regarding the maturity levels of fresh products, such as fruits and vegetables, can lead to products being discarded if they do not match customer expectations (ER2). Additionally, customer absence during delivery attempts increases food waste, particularly for perishables that cannot be redelivered or stored safely (OCR2, OCR5, OCR6, OCR7, ER1, ER2 and ER5).

Food packaging was mentioned as another critical sustainability factor, primarily due to its ecological nature. The reduction of material use and the promotion of reusability were highlighted as key problems in minimizing environmental impacts.

Participants stated that a major challenge in packaging design is the excessive air within numerous packages. This issue results in wasted transportation space and reduces the number of items that can be shipped in a single load. This inefficiency further increases the carbon footprint and raises the risk of bags bursting during transit due to the excessive air inside (OCR3). Cornflakes, for example, are often packaged in disproportionately large boxes compared to their contents, leading to wasted space and excessive use of materials. ER5 comments as follows:

Customer dissatisfaction with packaging further complicates the issue. Many consumers have expressed frustration with single-use paper bags, citing their limited practicality and environmental concerns (OCR7). Although reusable packaging is a promising alternative, the findings show it creates significant economic and social challenges.

Retailers report that customers often fail to return reusable boxes promptly (ER2), usually waiting until their next order. This behavior disrupts the circular system and creates delays and inefficiencies in the return cycle, resulting in financial losses (OCR4, OCR6, OCR7, ER4 and ER7). Managing reusable systems is also costly and labor-intensive, requiring resources for collection, cleaning, redistribution and additional warehouse storage (OCR6, OCR7 and ER2).

Social sustainability broadly refers to the well-being of individuals and communities, encompassing fairness, equity and customer satisfaction (Elkington, 1997). Participants did not report any challenges explicitly related to employee welfare, equity or community impact. However, they emphasized customer-facing issues as the primary social factor. Within the social dimension, two main factors were mentioned: product satisfaction and delivery punctuality and reliability.

Product satisfaction was highlighted as a critical factor, affected by product unavailability, the inadequacy of substitute products and difficulties with returns.

Supply chain disruptions, such as incomplete or late supplier deliveries and stock shortages, often result in unfulfilled orders (OCR6, ER3, ER4 and ER6). Mismatches between warehouse inventories and online listings further aggravate this issue, with products sometimes listed as available when they are not (OCR3, OCR7 and ER2). Resolving these discrepancies requires time-consuming administrative tasks, such as crediting customers for unavailable items (ER2 and ER6) or arranging substitutes (OCR3, OCR4, ER6 and ER7).

While substitutes are necessary, they carry the risks of dissatisfaction if the replacements do not meet customer expectations (OCR2, OCR6, OCR7 and ER2). Customers may reject replacements, leading to financial losses for the retailer and, in some cases, increased waste if perishable substitutes cannot be reused (OCR5, OCR7 and ER2). These problems can escalate further when substitutions are delivered later than the original order, which increases transport costs and diminishes customer trust (OCR2, OCR4, ER1 and ER7).

Product returns add another layer of complexity to maintaining customer satisfaction. Due to their nature, perishable goods are often non-returnable, resulting in direct losses for retailers (OCR7, ER2 and ER4). Some customers also exploit their right to withdraw from purchases, particularly for fragile goods, adding further complexity to returns management (OCR3 and ER1). As ER2 noted:

While effective customer service is crucial for maintaining customer loyalty, it demands a substantial investment of time and resources (ER3 and ER4).

Interview participants emphasize that meeting delivery time expectations is essential for customer satisfaction. However, various challenges undermine punctuality. According to experts, resource constraints and customer-induced delivery disruptions are major challenges that impact timely delivery.

Suppliers often cause delays. For example, late shipments can disrupt carefully planned delivery schedules (OCR6). Shortages of vehicles and drivers further exacerbate delays (OCR4 and ER1), particularly for same-day delivery requests (OCR5 and ER4).

Logistical difficulties are amplified when customers make short-term order changes (OCR5) or demand short delivery windows, reducing flexibility for unforeseen delays (OCR2, ER3 and ER6). Customer absence during delivery (OCR2, ER1 and ER3) or issues locating addresses (ER3) also pose significant problems, often resulting in longer delivery routes, increased transport time for re-delivery and additional time for restocking products (OCR2, OCR5, OCR6, OCR7, ER2, ER3 and ER5).

The analysis revealed no significant differences between omnichannel and electronic retailing regarding the ecological and social sustainability dimensions. In both fulfillment strategies, experts identified similar challenges related to food waste, packaging, product satisfaction and delivery reliability. However, notable differences emerged in the economic dimension. Omnichannel retailers reported particular difficulties with inventory management and order preparation for in-store pick-up, while home delivery providers identified last-mile transportation as their primary economic challenge. Based on these findings, the study proposes both cross-applicable measures, as well as fulfillment-specific measures tailored to the distinct economic pressures of each model.

The findings of this study suggest that sustainability challenges in OGR are distributed across all three TBL dimensions and are closely interrelated, with one factor often influencing several others. Building on the seven critical factors identified, this section examines improvement measures recommended by participants and discusses how these measures address and interconnect the identified sustainability challenges. To answer RQ3 and RQ4, we developed an active-passive matrix, which incorporates participants' recommended measures and structures targeted improvements addressing at least two different sustainability factors. The matrix rows represent the improvement factors, while the columns indicate the factors that will be positively affected when the recommended improvement measure is implemented. This structure illustrates how progress in one factor may generate positive effects across several other sustainability factors.

The recommended measures also pointed to an additional social factor that emerged only at the recommendation stage of the analysis. This new factor (people benefits) encompasses occupational health and safety, customer justice and fairness, community engagement and employee satisfaction. Because this factor was not identified as a challenge in the first phase of the analysis, it does not represent an improvement factor itself. We added the new factor as an additional column in the matrix to highlight how improvements in other factors positively influence it.

Building on this analysis, we derived a set of recommended improvement measures and identified three factors that appeared particularly influential for fostering SOGR: optimized order picking, innovative packaging and punctuality and reliability. Furthermore, food waste appeared to have the greatest improvement potential because multiple other factors within the matrix influenced it. Therefore, all three dimensions of sustainability have far-reaching implications that converge on food waste (see Table 3).

In the following sections, we examine the three most impactful factors of SOGR in detail, emphasizing their interrelationships across the TBL's economic, ecological and social dimensions. We then consider recommended measures for different sustainability factors to reduce food waste in online grocery operations, as this factor emerged as the one with the greatest improvement potential.

Order picking is a fundamental logistical process in SOGR, directly impacting storage efficiency, last-mile transportation, food waste, product satisfaction, delivery punctuality and reliability and providing people-related benefits. Despite its pivotal role, it remains underexplored in sustainability research. The interviews conducted in this study and prior literature highlight its critical importance (Fikar, 2018; Rodríguez-García et al., 2023).

One key area of improvement identified in this study is the integration of advanced tracking and scanning systems during picking (PICK1), which enables real-time data capture (OCR5 and ER2) and may improve coordination between inventory management and order picking processes.

Accurate and timely picking data provides valuable insights into customer behavior, product preferences and peak demand periods. These insights can improve demand forecasting, adjust stocking strategies and refine promotional campaigns based on customer needs (Mohammed et al., 2025a; Seghezzi et al., 2022).

Product picking validation (PICK2) has also proven to be an effective measure to reduce errors, such as incorrect or incomplete orders (ER2 and ER7), while improving work efficiency and customer satisfaction (Mkansi and Nsakanda, 2023). Validation also helps maintain accurate warehouse stock levels and reduces food waste by ensuring that the correct items are delivered to customers (ER4 and ER5).

Optimizing the order-picking sequence (PICK3) emerged as another measure with significant opportunity to enhance sustainability (Mkansi and Nsakanda, 2023), particularly when handling cooled, frozen and fragile goods. Picking temperature-sensitive items last minimizes refrigeration times, reduces energy consumption and preserves product quality.

Furthermore, this measure lowers the risk of damage and food spoilage during transport for sensitive items and ensures products reach customers in good condition (ER2 and OCR5).

Improving the picking sequence not only ensures that the cold chain is maintained and sensitive products remain intact (OCR4, OCR5 and ER2) but also increases vehicle loading efficiency (OCR7 and ER2), which enhances space utilization (ER4, ER5 and ER7) and reduces the number of trips required (OCR4, ER2, ER4, ER5 and ER7).

Unlike in traditional grocery shopping, where customers inspect products, online shoppers rely entirely on the retailer to select quality items (Siragusa and Tumino, 2022). Therefore, careful attention to product quality during picking (PICK4) is essential to enhance customer satisfaction and to minimize spoilage and food waste (ER2).

In addition, explicitly asking customers about their preferences for ripeness and freshness (PICK5) during the ordering process (OCR6), as also suggested by Mkansi and Nsakanda (2023), can improve the picking experience and reduce waste by better aligning with customer expectations.

When a product is unavailable, tools that suggest substitutes (PICK6) of similar price and quality or offer customers alternative replacement options at the order stage, can streamline the picking process, reduce food waste and improve customer satisfaction by minimizing unwanted substitutes (OCR4).

Furthermore, consolidating multiple orders during picking (PICK7) may enhance efficiency and improve delivery punctuality (OCR1 and OCR5). Batch or zone picking are two commonly applied methods used for this purpose. While batch picking reduces picker travel time by grouping orders, zone picking speeds up item location and minimizes search time by assigning pickers to specific areas (Zhang et al., 2023).

Finally, for omnichannel retailers performing picking activities in brick-and-mortar stores, the findings suggest scheduling these activities during off-peak shopping hours or establishing designated in-store picking lanes or areas (PICK8). These measures can significantly improve delivery punctuality and reliability, benefiting the pickers and customers shopping in-store by reducing congestion and avoiding conflicts over space and products (OCR4).

Packaging innovations appear to influence SOGR operations in multiple ways. Improvements in packaging affect not only storage efficiency, picking and last-mile transportation but also food waste, product satisfaction and the safety and well-being of employees and customers. Despite this wide-ranging impact across the TBL dimensions, the role of packaging in promoting sustainability remains underexplored in online grocery research (Winkler et al., 2023). Recent food-waste-focused studies further emphasize that packaging decisions are a critical upstream determinant of sustainability outcomes in e-commerce food supply chains (Mohammed et al., 2025a, b).

One recommendation identified in this study is tailoring packaging to the size and type of goods (PACK1), allowing for more efficient storage, optimized warehouse capacity and maximized vehicle space utilization (ER5). Minimizing wasted space in delivery vehicles can reduce the number of required trips, thereby lowering transportation costs and significantly decreasing greenhouse gas emissions – a critical global issue also emphasized by Zhang et al. (2022).

In addition to improving efficiency, sustainable packaging practices may help mitigate the environmental costs associated with excessive packaging waste. Akkerman et al. (2010) highlight the significant environmental impact of packaging materials in SOGR, where additional materials are often used to ensure food quality and safety. This study finds that introducing collapsible, stackable reusable packaging (PACK2) not only reduces the space required in warehouses and transport vehicles (OCR4) but also saves money and addresses customer dissatisfaction with excessive cardboard and single-use materials (OCR1, OCR2, OCR4, OCR5, OCR6, ER1, ER3, ER4, ER5, ER6 and ER7). These findings align with recent evidence showing that improper packaging is one of the main causes of food waste reported by consumers in online grocery channels (Mohammed et al., 2025b).

Furthermore, robust and well-designed packaging with reduced air content (PACK3) improves sustainability by facilitating automated picking processes (OCR3). Better-designed packaging enables machines to handle products with minimal risk of damage (ER2 and ER7). Such packaging can help secure goods during transit, ensuring safe delivery while protecting employees and customers from potential injuries caused by poorly packaged or damaged products (ER4 and ER5).

Innovations in cold chain packaging technologies are particularly impactful in reducing food waste and enhancing operational efficiency. Grant et al. (2014) and Heldt et al. (2021) underscore the importance of maintaining unbroken cold chains to preserve the quality and safety of perishable goods. Advanced packaging solutions, such as packaging equipped with condition monitoring sensors (ER1, ER4, ER6 and ER7) and compartments with varying temperature zones (PACK4) (ER3), help to ensure the freshness and safety of perishable items during transport.

Such smart packaging solutions are increasingly recognized as an effective means of identifying temperature deviations, preventing quality issues and reducing food waste in online grocery logistics (Mohammed et al., 2025a). These technologies minimize spoilage, enhance customer satisfaction and promote safe delivery practices that protect public health (ER1).

Finally, theft-resistant and protective packaging for fragile items (PACK5), such as eggs, glass bottles or fresh produce, further supports sustainability. This packaging measure ensures that customers receive excellent-quality products, thereby reducing complaints, returns and replacements. Protective packaging, in turn, minimizes unnecessary transportation and mitigates the risk of food waste, while also enhancing customer trust and satisfaction (OCR3).

Punctual and reliable delivery is a cornerstone of SOGR. Traditionally, this has been examined primarily from an economic perspective, focusing on reducing costs and optimizing vehicle utilization (Fikar et al., 2021; Pan et al., 2017). However, the findings of this study demonstrate that punctual and reliable delivery has far-reaching implications across all three dimensions of sustainability. These effects are noticeable in storage efficiency, order picking, last-mile transportation, food waste reduction, product satisfaction and customer equity (a component of people benefits).

One important measure identified in the interviews is accurate demand and delivery-time forecasting (PUNCT1), which helps prevent stockouts and overstocking. This measure reduces unnecessary storage times and minimizes food spoilage (OCR6). Furthermore, precise delivery forecasts enable warehouses to prioritize picking activities according to delivery schedules, facilitating smooth dispatches without bottlenecks or delays (OCR2 and OCR4).

More precise delivery times also increase first-time delivery success rates (PUNCT2), which is critical for sustainability.

High success rates may reduce the need for costly and environmentally harmful return trips, reducing transport costs, vehicle emissions and congestion (OCR4 and OCR5). At the same time, they reduce the operational complexity of synchronizing and replenishing stocks in real-time (OCR1, ER4, ER5 and ER7). Consistent with this, Hübner et al. (2019) and Jiang et al. (2021) also emphasize that missed deliveries create additional routes, exacerbate traffic congestion, increase energy consumption and generate higher CO₂ emissions, all escalating delivery costs. In the case of perishable goods, precise delivery minimizes the time spent outside optimal temperature ranges, preserving product quality, reducing product complaints and limiting food waste (OCR7, ER2, ER3 and ER7). However, Trienekens et al. (2017) and Fikar et al. (2021) caution that providing too many time slot options can reduce route efficiency by increasing transport distances and emissions. Likewise, Schnieder et al. (2023) argue that eliminating time slots can improve delivery routes and lower CO₂ emissions, although this may undermine service quality and raise the risk of customer absence.

When customers are unavailable for delivery, donating unsold perishable goods to charitable organizations (PUNCT3) has emerged as a practical and socially beneficial solution (OCR6).

This practice facilitates warehouse processes and mitigates food waste resulting from prolonged delivery routes or inadequate cooling, but also supports local communities and strengthens retailer-community relations (OCR2).

In cases where products are unavailable, offering customers adjusted delivery times or the option to reschedule orders (PUNCT4) emerged as an effective measure to shorten picking times and improve service quality (OCR3, OCR7, ER2 and ER3).

Collaboration with local logistics service providers (LSPs) familiar with the delivery area (PUNCT5) offers another way to enhance punctual and reliable delivery. Experienced LSPs know how to navigate busy, narrow streets and can identify optimal parking solutions, even in areas with limited accessibility (ER6). Extending this perspective, Tudisco et al. (2025) show that the flexible use of on-demand vehicles from third-party logistics providers enables retailers to improve routing adaptability and delivery reliability while facilitating the adoption of more sustainable delivery options. Importantly, this flexibility allows companies to enhance punctuality and environmental performance without requiring substantial upfront investments in their own delivery fleets.

Training LSP drivers or employing dedicated in-house delivery personnel (PUNCT6) can mitigate last-mile delivery challenges.

Educated drivers are better equipped to handle fragile products, reducing the risk of damage and associated food waste while increasing customer satisfaction (ER6). Moreover, employing in-house drivers gives the company greater control over occupational health and safety standards, thereby contributing to the social sustainability of delivery operations (OCR5).

The recommended improvement measures for enhancing picking, packaging, as well as punctuality and reliability are summarized in Figure 1. Implementing these measures enables retailers to address economic, ecological and social challenges in an integrated manner, fostering more balanced and sustainable online grocery operations.

Closely examining the proposed measures reveals that the factors most affected and offering the greatest potential for enhancement are last-mile transportation, food waste and product satisfaction. However, a comprehensive evaluation across the seven critical sustainability factors with their respective measures indicates that food waste emerged as the sustainability factor with the greatest potential for improvement.

In addition to the most impactful factors (picking, food packaging and punctuality and reliability), further reductions in food waste can be achieved through targeted improvements in storage, last-mile transportation and product satisfaction.

Minimizing food waste in storage requires systematic organizational and real-time monitoring. Establishing dedicated storage zones for sensitive products or those with short best-before dates (STOR3) (OCR7, ER3 and ER7) and placing items with the shortest shelf life at the front shelves (STOR4) (ER4, ER5 and ER7) helps ensure timely rotation and consumption.

Real-time temperature monitoring (STOR5) within storage facilities (ER1, ER2, ER4 and ER6) also plays a crucial role in preserving product quality. In addition, a more accurate inventory quantity (STOR6) can prevent the problem of overstocking and reduce spoilage (ER4, ER5 and ER7).

These practices are strongly supported by recent research emphasizing the importance of enhanced forecasting methods for effective storage management and food waste reduction in e-commerce food supply chains (Mohammed et al., 2025a, b).

Efficient last-mile logistics are vital for protecting perishable goods and reducing food waste. Real-time temperature monitoring (LMD1) during delivery (ER1, ER4, ER6 and ER7) and the availability of emergency cooling systems (LMD2) in vehicles (ER1 and ER5) help to maintain the integrity of the cold chain. Alternative delivery methods, such as temperature-controlled smart lockers (LMD3) (OCR5, OCR7 and ER5) and deliveries to alternative locations (LMD6) (e.g. workplaces or public institutions) (OCR2, OCR4 and OCR6) further mitigate the risk of spoilage.

Planning deliveries during low-traffic periods (LMD7) (OCR6) and using route optimization software that accounts for unloading complexities and traffic density (LMD8) (OCR7, ER2, ER4, ER5 and ER7), coupled with real-time vehicle tracking (LMD9) (ER4 and ER7), reduces delays and shortens the transportation time of refrigerated goods (LMD4), preserving food quality (ER2). Complementing these operational measures, Ko et al. (2025) emphasize that investments in delivery-supporting infrastructure, such as designated parking spots and pick-up counters, can significantly improve delivery accuracy and efficiency, which in turn reduces food waste caused by delays, failed deliveries or improper handovers.

Aligning deliveries with customer expectations also helps to reduce waste. Allowing customers to define acceptable replacement products (SAT1) (OCR4) and specify ripeness levels for perishables (SAT2) (OCR6) helps to ensure that the delivered goods match their preferences.

Furthermore, discounts on items nearing their best-before dates (SAT3) (OCR6 and ER3) encourage timely sale and consumption, lowering waste levels.

These findings align closely with recent recommendations that online grocery retailers should systematically offer a discounted process for near-expiry products as part of an integrated food waste prevention strategy (Mohammed et al., 2025a).

The interrelationships among the identified critical sustainability factors and their corresponding improvement measures underscore the complexity of achieving SOGR. Rather than addressing sustainability challenges in isolation, the results suggest that an integrated approach across all three TBL dimensions is necessary.

While the ecological and social dimensions appear to be largely independent of the chosen fulfillment model, the economic dimension is notably shaped by it. These results are consistent with the findings of Rodríguez-García et al. (2023), who noted that retail store-based strategies incur higher picking costs, while warehouse-based strategies are more affected by delivery costs. This finding suggests that a differentiated approach to sustainability improvement is necessary. While certain measures, particularly those targeting ecological and social challenges, can be applied across fulfillment models, the relevance of economic sustainability measures varies depending on the specific fulfillment strategy employed.

This study set out to understand why online grocery retailers face challenges in developing SOGR, which factors are critical for achieving it, and which operational measures can improve sustainability performance. Drawing on expert interviews with industry practitioners, the study provides empirical insights into the operational challenges of the cost-conscious and highly competitive German online grocery market. In doing so, our study addresses the limited availability of qualitative research in this field.

The findings indicate that SOGR challenges arise primarily from the operational complexity of coordinating economic efficiency, ecological responsibility and customer-oriented service requirements within highly time-sensitive supply chains (RQ1). In such logistics-intensive environments, operational decisions frequently generate trade-offs and synergies across sustainability dimensions. Seven critical sustainability factors were identified across the three dimensions of the TBL framework (RQ2): storage, picking and last-mile delivery (economic); food waste and food packaging (ecological); and product satisfaction, as well as delivery punctuality and reliability (social). In contrast to much of the existing literature, which focuses primarily on last-mile delivery, the findings highlight the importance of upstream logistics processes such as storage and order picking, demonstrating how multiple supply chain activities jointly influence sustainability outcomes.

To address the interdependencies between the critical sustainability factors identified, this study developed an active-passive matrix that maps recommended operational measures and illustrates how improvements in one area can positively influence multiple sustainability factors simultaneously (RQ3). By organizing the sustainability factors and improvement measures in this way, the study provides a more integrated understanding of sustainability in online grocery logistics. It helps address the fragmentation previously observed in the literature, where economic, ecological and social sustainability dimensions are often examined separately. During this process, an additional factor (people’s benefits) was identified on the passive side of the matrix, complementing the social sustainability dimension. The identification of this factor further addresses the limited attention given to social sustainability in existing SOGR research by highlighting broader social outcomes such as occupational safety, fairness, community engagement and employee well-being.

The analysis further revealed three factors that play a central role in improving SOGR: order picking, packaging design and delivery punctuality and reliability (RQ4). Order picking emerged as the most impactful economic factor. Measures such as automation, optimized picking sequences, picker training, quality control and the inclusion of customer-defined preferences can improve cost efficiency, reduce waste and enhance delivery accuracy. Packaging improvement was identified as the most impactful ecological factor. In particular, reusable, tailored and cold-chain-enabled packaging designs can improve space utilization, reduce food waste and emissions and enhance product protection during transportation. Delivery punctuality and reliability emerged as the most impactful social factor, as accurate forecasting, precise delivery times, trained or dedicated drivers and collaboration with local logistics partners increase first-attempt success rates, reduce emissions and support equitable and safe delivery practices.

In addition to these highly influential factors, food waste emerged as the sustainability factor with the greatest improvement potential, as it is affected by multiple operational processes across the supply chain. Beyond improvements in picking, packaging and delivery punctuality, enhancements in storage practices, last-mile transportation and customer product satisfaction were also identified as particularly effective in reducing food waste.

Moreover, the findings contribute to a more comprehensive understanding of fulfillment models in OGR. While previous research has largely examined home delivery and click-and-collect systems in isolation, this study reveals that fulfillment models share common challenges in the ecological and social sustainability dimensions, yet diverge meaningfully in terms of economic sustainability. Based on these insights, this study proposes both cross-applicable improvement measures that address shared sustainability challenges, as well as tailored recommendations that account for the distinct economic pressures of each fulfillment model.

This study contributes to the literature on SOGR by providing a more integrated perspective on sustainability management in logistics-intensive retail systems. Previous research has often examined the economic, ecological and social dimensions of sustainability separately. For example, studies have focused on cost-efficient logistics and fulfillment design (e.g. Auf Der Landwehr et al., 2024; Rodríguez-García et al., 2023; Wollenburg et al., 2018), on environmental impacts such as carbon footprint and resource use (e.g. Mohammed et al., 2025b; Motte-Baumvol et al., 2023; Siragusa and Tumino, 2022; Zhang et al., 2022) or on customer service quality and accessibility (e.g. Fikar et al., 2021; Pan et al., 2017; Vyt et al., 2017). By identifying and analyzing sustainability factors across all three TBL dimensions simultaneously, this study highlights the systemic interdependencies between operational decisions and sustainability outcomes in online grocery supply chains.

Second, this study advances the theoretical understanding of sustainability management in OGR by introducing an active-passive matrix that conceptualizes how operational measures interact across multiple sustainability factors. Rather than viewing sustainability improvements as isolated interventions, the matrix illustrates how certain operational factors can function as leverage points that influence multiple outcomes simultaneously. While much of the existing literature emphasizes trade-offs between sustainability dimensions, the findings of this study highlight that many operational improvements can generate synergies across economic, ecological and social outcomes. This perspective refines existing sustainability research by demonstrating that coordinated operational improvements can generate sustainability synergies rather than inevitable trade-offs.

Third, the study distinguishes between sustainability factors that exert the greatest systemic influence and those that offer the greatest improvement potential. This distinction provides a more nuanced theoretical perspective on prioritizing sustainability interventions within complex supply chain systems. Notably, the analysis revealed that one particularly influential factor emerged within each sustainability dimension, highlighting the balanced importance of improvements across all three pillars of the TBL framework.

Finally, this study contributes to theoretical discussions on social sustainability in OGR by identifying “people benefits” as an emergent outcome of operational sustainability measures. While social challenges initially appeared limited to customer satisfaction and delivery reliability, the analysis revealed that several operational improvements generate indirect social benefits. This finding suggests that some social sustainability outcomes may remain latent until examined within a broader system-level perspective.

For practitioners, the active-passive matrix developed in this study provides a practical decision-support tool that can help managers prioritize sustainability initiatives in online grocery operations. By identifying cross-functional leverage points, the matrix suggests that investments in order picking processes, packaging design and delivery reliability can simultaneously improve cost efficiency, reduce food waste and emissions and enhance customer satisfaction. Rather than addressing sustainability challenges through isolated operational improvements, managers should adopt a holistic perspective that considers the interdependencies between supply chain processes.

The findings also contribute to a more comprehensive understanding of fulfillment models in OGR. While previous research often examines home delivery and click-and-collect systems in isolation, this study reveals that different fulfillment models share common challenges in the ecological and social sustainability dimensions, yet diverge in terms of economic sustainability. These insights carry practical relevance for retailers seeking to develop targeted sustainability strategies that account for the specific characteristics of their business model.

Moreover, the insights derived from this study suggest that many of the identified challenges are not exclusive to SOGR. Similar logistical challenges arise in other e-commerce sectors characterized by perishable or fragile products, frequent deliveries and high service expectations (e.g. meal kit delivery or online pharmacy). Consequently, several of the recommended operational measures may also be transferable to these related industries.

Overall, the findings emphasize that achieving SOGR requires coordinated operational improvements across multiple supply chain activities. Sustainability improvements in OGR should therefore not be viewed solely as trade-offs between competing objectives but can also generate mutually reinforcing benefits across multiple sustainability dimensions.

Despite its contributions, this study has some limitations that open avenues for future research. First, as the findings are based on qualitative data focused on the German online grocery market, they may not be generalizable to other countries with different retail landscapes and consumer behaviors. Although the findings were validated by the experts interviewed, the geographical specificity of the study suggests that further research is needed to increase its global relevance.

Second, as Grounded Theory relies solely on what emerges from data, we reported only storage-related challenges explicitly mentioned by participants – namely, inventory updating and storage capacity. Other potentially relevant storage concerns, such as temperature control, sanitation, pest control, cross-contamination or employee safety, were not raised during the interviews and therefore did not appear in our findings. These issues remain important avenues for future research, particularly in contexts with more pronounced storage-related risks.

Third, while the qualitative approach employed in this study provides rich, in-depth insights, the recommended measures require further validation using quantitative methods. Future research should conduct cost-benefit analyses and life-cycle assessments to substantiate the impact of the recommended sustainability measures. Simulation-based studies could also examine the influence of order-picking optimizations, packaging innovations and more punctual and reliable deliveries on supply chain performance under different market conditions and demand fluctuations.

Fourth, although this study focuses primarily on logistical solutions, the potential of emerging technologies to enhance sustainability outcomes remains an exciting and underexplored research area. Technologies like artificial intelligence, blockchain and the Internet of Things offer promising opportunities to improve inventory management, enable real-time tracking, reduce waste and benefit employees and customers. Future studies should investigate how retailers can leverage these technologies to enhance the efficiency and sustainability of online grocery logistics.

Fifth, while this study adopts a retailer-centric perspective, future research should investigate the customer viewpoint to understand the impact of consumer preferences, behaviors and willingness to pay on the implementation and effectiveness of the recommended measures. Specifically, examining customer responses to dynamic pricing for short-dated goods, acceptance of reusable packaging systems and flexibility regarding delivery options and windows could provide valuable insights into the influence of demand-side factors on retailer strategies and achieving sustainable outcomes⁴.

The authors gratefully acknowledge the valuable feedback received from participants at the European Research Seminar (ERS) 2025, held in Verona, Italy, which helped strengthen earlier versions of this manuscript.

1. Could you briefly describe your role and responsibilities within the company?

   • How long have you been working for the company?

   • How much total work experience do you have in your current position?

2. How is your organization structured regarding online grocery retailing?

3. When did you establish online grocery retailing? Why did you decide to do this?

4. What proportion of your grocery sales are generated online compared to in-store?

5. What kind of food do you offer online and why?

6. Which fulfillment methods does your company currently offer for online grocery sales (e.g. home delivery, click-and-collect, others)?

   • Why did you decide to offer exactly these methods?

   • Are other forms planned for the future?

   • What things need to be paid particular attention to in the processes?

7. What are the key logistical processes involved in fulfilling online grocery orders in your company?

1. What economic or financial challenges does your organization face in online grocery logistics, and why?

   • e.g. storage, picking, transportation, returns, pricing, delivery time, collaboration

2. How do these challenges impact your company?

3. Can you describe any initiatives or measures your company has implemented to improve the economic sustainability of its online grocery operations?

4. What recommendations would you make to address these economic challenges and why?

1. What ecological challenges do you observe in your online grocery logistics and why?

   • e.g. food waste, packaging, emissions

2. How do these challenges impact your company?

3. Can you share examples of successful measures your company has implemented to reduce environmental impact?

4. What actions or recommendations would you propose to improve ecological sustainability in e-grocery logistics, and why?

1. What social or community-related challenges arise from your online grocery operations and why?

   • e.g. customer satisfaction, accessibility, employee well-being

2. How do these challenges impact your company?

3. Are there initiatives aimed at improving the social impact of your online grocery business?

4. What additional measures or recommendations would you suggest to enhance the social sustainability of e-grocery logistics, and why?

Is there anything else you want to share regarding sustainability in online grocery retailing that we have not yet discussed?

(Authors' own work)