The purpose of this paper is to investigate the effectiveness of NaOCl and KMnO4 at two levels in reducing the microbial load of coriander leaves.
Fresh coriander leaves procured from various markets were intensively sampled and administered to wash treatments with tap water and sanitizers at two levels. Hi media pre plated plates were used for determination of TPC (Total Plate Count), Staphylococcus aureus, Listeria, Salmonella, Shigella and coliforms.
Unwashed coriander leaves showed TPC beyond the acceptable limits of 105 CFU/g. Bulk washing (10 g sample dipped in 1 litre tap water for 5 minutes) did not significantly reduce TPC and any of the pathogens. TPC decreased significantly by 1 log cycle up on treatment with 200 ppm NaOCl and 100 ppm KMnO4. Staphylococcus aureus could be reduced more effectively with 100 ppm of KMnO4; Listeria monocytogenes and Salmonella showed significant reductions (P<0.05) using both sanitizers. Shigella decreased by more than 1 log cycle when treated with 100 ppm KMnO4.
Tap water is not sufficient to reduce the microbial load of fresh coriander. Use of 100 ppm NaOCl and 50 ppm KMnO4 may be considered to reduce the pathogenic load of coriander leaves. Since reduction of pathogenic load by 1 log cycle is insufficient, other means of disinfecting the raw produce need to be tested. Also, use of good irrigation practices and aseptic post harvest techniques cannot be ignored.
This is an original study, wherein use of sanitizers should be promoted in order to reduce the microbial load of coriander leaves.
