The consumption of ready-to-eat side dishes is rapidly growing in South Korea. These foods are particularly vulnerable to microbiological contamination as they are often cooked without any treatment, such as heating or stored at room temperature after cooking. Hence, in 2022, we analyzed the ready-to-eat side dishes sold in Gyeongsangnam-do, South Korea for microbiological contamination. We collected 100 samples from supermarkets in 7 cities, and then examined them for presence of food-borne pathogens and sanitary indicator bacteria. In the analysis of the food-borne pathogens, Bacillus cereus and Clostridium perfringens were isolated from 51 samples (51.0%) and 3 samples (3.0%), respectively. However, both quantitatively met the Korean Food Standards Codex. Genes of five different enterotoxins and one emetic toxin were analyzed from the 51 isolated B. cereus strains. We detected enterotoxin entFM (100.0%), nheA (94.1%), hblC (58.8%), cytK (56.9%), and bceT (41.2%) in 51 isolates, and emetic toxin gene, CER, in only one (2.0%) isolate. We did not detect C. perfringens toxin gene (cpe) that causes food poisoning in any one of the three C. perfringens isolates. In the case of sanitary indicator bacteria, Kimchi had the highest levels of total aerobic bacteria and coliforms, followed by Saengchae, Jeotgal, Jeolim, Namul, and Jorim, respectively. We counted total aerobic bacteria at two different storage temperatures (4oC and 20oC) to determine the effect of storage temperature. When stored at 20oC, total aerobic bacteria count increased in most of the ready-to-eat side dishes, except for Jeotgal. This result conclusively shows the need for refrigerating the ready-to-eat side dishes after purchase. Further research is needed to assess the risk and safety of the ready-to-eat side dishes available in the market and determine appropriate safety management practices.
The saturated fatty acids(arachidic acid, stearic acid, and palmitic acid) were repeatedly applied on water surface, and their π-A isotherms and Maxwell displacement current(MDC) were measured to identify the effect of the number of carbons of fatty acids on the properties of Langmuir films. The saturated fatty which contain higher carbon number showed higher MDC peak, and the less carbon it contains, the higher surface pressure they show. It was found the maximum of MDC peaks was as the molecular area just before the surface pressure increases in compression cycles of saturated fatty acids.