microbial load evaluation of fresh-cut vegetables during processing steps in a vegetable processing plant using minimally processing approach

the number of vegetable processing plants has been increased during recent years in iran as many other countries. on the other hand, fresh vegetable products are susceptible to microbial contamination after harvest, processing, handling, packing and distribution. the aim of this study was to determine and evaluate the level of microbial load of vegetables during different cleaning steps in a fresh-cut vegetable processing plant and to identify the critical points in the process lines and operating areas. samples were taken from the plant before and after washing, disinfection, cutter, drying and packaging and kept in ice pack and delivered to the laboratory. the samples were analyzed for mesophilic aerobic count, yeasts and moulds, lactic acid bacteria, total coliforms, enterobacteriaceae, e. coli and staphylococcus aureous as well as for the presence of salmonella, according to the standard guideline. the amounts of total aerobic bacteria, enterobacteriaceae, e. coli, yeasts and moulds on surfaces and air were also determined. results showed that bacteria as well as yeasts and moulds levels were decreased after washing and disinfectation up to 1 and 1.5 log10, respectively, but after that, the microbial load was increased due to secondary contamination. during all steps, salmonella was not detected, but e. coli detected in some of the steps and s. aureous was detected at all steps. the highest levels of total aerobic bacteria, enterobacteriaceae, e. coli, yeasts and moulds were detected on the equipments (cutters, peeling, centrifuge machines, etc.). different hygienic areas should be separated enough to allow maintenance of good hygiene in cleaner areas in primary washing steps. despite this, the results showed that there is a vital need to improve cleaning and hygienic practices in vegetable processing plants. several practical recommendations were given for cleaning, design of production lines, training of employees and surface hygiene.