Understanding the routes of contamination of ready-to-eat vegetables in the Middle East

- A high prevalence of Escherichia coli and total coliforms was found from farms to market.
- E. coli and total coliforms counts significantly increased in post-harvest washing.
- Pathogenic organisms were detected on fresh produce along the supply chain.
- Post-harvest wash process is identified as a pathway of pathogens on fresh produce.
- Untreated chicken manure are likely to be a source of the high occurrence of Staphylococcus aureus.

In the developing countries, inaccessibility to safe water, lack of agricultural infrastructures and limitations to implementing good agricultural practices (GAP) are persistent challenges. To understand the spread of hazards and identify critical areas of transmission in the food chain, a total of 90 samples of raw salad vegetables (parsley, lettuce, radish) were collected from farms and post-harvest washing facilities (n = 12) in an extensively cultivated area in Lebanon, the Bekaa Valley and from wholesale market stalls traced back to surveyed fields. Our results showed high geometric mean indicator levels ranging from <0.7 to 7 log CFU/g (Escherichia coli), 1.69-8.16 log CFU/g (total coliforms), <0.7-8.39 log CFU/g (Staphylococcus aureus). The mean counts of total coliforms and E. coli on fresh produce followed an increasing trend from fields to the markets indicating potential sources of faecal contamination throughout the food chain. Of more concern was the presence of pathogens Listeria monocytogenes (14%) and S. aureus (45.5%) in fresh produce from harvest to retail, and Salmonella spp. was detected in 6.7% of the raw vegetables from the post-harvest washing areas. These results along with our observations highlight shortfalls in hygienic farming and postharvest practices, including the use of inappropriately treated manure and chicken litter to fertilize the crops on the fields which contributed to the high levels of S. aureus in the product at retail. Unregulated use of wash water, inadequate transportation and storage conditions with risks of cross contamination was also identified. Suggested control measures should mitigate the risks at the source and put emphasis on developing strict policies on monitoring the safety of water sources and on the application of the good agricultural and hygienic practices (GAP, GHP) on primary production stages, washing, transportation and storage at retail.