Investigating the Efficiency of Different Steps of the Most Common Method for Disinfecting Vegetables to Reduce the Microbial Population

Background & objectives:

Considering the importance of sanitizing vegetables before consumption, this study aims to evaluate the effectiveness of different stages of the most common vegetable disinfection methods in Iran in reducing total coliform and fecal coliform for the most consumed edible vegetables.

Three stages of disinfection were done, including
Scraping and pre-wash of vegetables (first step),
Separation of parasites by 3-5 droplets of detergent per liter for 5 minutes (second step), and
Disinfection of vegetables with calcium hypochlorite solution (200 mg/l free chlorine) for 5 min (third step).
Finally, disinfected vegetables were washed out with water. MPN test was used to determine total and fecal coliform. The efficiency of each stage was determined using the difference between total and fecal coliforms before and after each and total disinfection stage. 

The fecal coliform amount did not reach zero even after all the disinfection steps in vegetables with more foliage and hidden holes (such as basil and onion). Besides, according to this study's results, radish, onion, and coriander leaves had the highest contamination, and lettuce had the lowest total and fecal coliform. The highest total coliform removal efficiency related to beets (93.3%) was obtained under calcium hypochlorite disinfection, and the highest fecal coliform removal efficiency related to leeks, parsley, and beets (100%) under calcium hypochlorite disinfection.

To achieve the highest efficiency in reducing microbial agents in vegetables, it is necessary to complete the different disinfection stages following its instructions. In this regard, the efforts of the media and health experts are essential.