Microbial Behavior in Cambodian Homemade-style Pickles

<p>Pickled products made using vegetables are popular in Cambodia. Many types of homemade pickles are sold at wet markets. Our previous study showed that pickles are seriously contaminated by microbes, including food poisoning bacteria. Such contamination may depend on several factors. The objectives of this study were to investigate the levels of contaminating microbes and their growth patterns in pickles prepared according to traditional Cambodian recipes and to suggest an improved method to ensure the microbial safety of homemade pickles. Three kinds of pickles, namely cucumber pickles with or without fish sauce and bok choy pickles, were prepared following the methods used by local people. Five sample bottles for each kind of pickle were prepared to observe changes in their characteristics over time. The Brix values, salt concentrations, and pH of the samples were measured. Next, we conducted microbiological examination of the samples by testing the presence of total viable bacteria, coliforms, and fungi. More than 5.00 log₁₀ CFU/g of total bacteria were detected in all pickle samples at day 0; moreover, the number of bacteria increased until day 4. A similar concentration of coliforms was observed. Some samples tested positive for fungi. In conclusion, all samples were contaminated by harmful microorganisms that may cause food spoilage. The results of this study revealed that microbial growth occurred in all tested pickles, resulting in a high risk of food spoilage and food poisoning. We suggest that an additional step of pasteurization would help provide microbiologically safe products. Moreover, use of food additives that do not alter the taste of pickles may allow maintenance of low levels of microorganisms.</p>