Study On Elimination Of Salmonella Typhimurium On Fresh-cut Cucumber Slices

Fresh-cut vegetables and fruits with freshness, nutrition, convenience and high edibility rate are popular with American and Japanese. They are becoming fashionable in china, consumption increasing. The safety and sanitation of fresh-cut vegetables and fruits is an important part of safety and sanitation of food. The level of microorganism is one of key factors for the quality of fresh-cut vegetables and fruits. The processing of vegetables and fruits may increase microbial spoilage through transfer of microflora on the outer surfaces to the interior tissue where microorganisms have access to nutrient-laden juice. Occurrence of microbial contamination of fresh-cut vegetables and fruits, would not only pose a threat to the health of consumers, but also may lead to social problems. So it's necessary to study a effective and safe method to control the number of microbes in fresh-cut vegetables and fruits.Bdellovibrio are predators of other bacteria just like the phage, with invading into the host cells and lying the host bacteria to cause it death, and they can ly most of gram negative bacterium. So Bdellovibrio have great use of prospects to control the pathogens in food. In this study, we aimed to examine their potential in controlling growth of Salmonella Typhimurium on fresh-cut cucumber slices, compared to hydrogen peroxide and high hydrostatic pressure treatment. The sensory evaluation, the pH value and the biological analysis were detected.The result showed with 2.5% and 5.0% hydrogen peroxide treated groups had good effects on controlling the pathogen compared to the control, and the exeperimental groups could extend the Shelf-life of fresh-cut cucumber slices 12h longer than the control. While within the timespan of 48h the both exeperimental groups were not significantly different. In sensory evaluation, because of hydrogen peroxide as a chemistry would cause remains. And this would not only be harmful to health, but also effect the flavor. The pH values showed no significant differences among control and exeperimental groups. The high hydrostatic pressure treated group could extend the Shelf-life of fresh-cut cucumber slices 12h longer than the control. However, and the effect of hydrostatic pressure may cause the exeperimental group little crisper than the control. The pH values showed no significant differences between control and exeperimental group. 5 strains of Bdellovibrio as a test material, selected 1 strain of which can use Salmonella Typhimurium as host. Considering the lysis time, the number of lysis spot and other factors, we chose BD2GS and used Salmonella Typhimurium as its host. After BD2GS adapt to the new host, the equivalent of ten times and the equivalence of the Salmonella Typhimurium's concentration of BD2GS's concentrated liquid were added to eliminate Salmonella Typhimurium of fresh-cut cucumber slices in the test. The results showed that the exeperimental groups could extend the Shelf-life of fresh-cut cucumber slices 12h longer than the control. The high-done group had Faster onset than the low-done group. however, they were no significant difference within the timespan of 36–48h (p>0.05). The sensory evaluation indicated that the exeperimental groups could be better maintained the original flavor than that of the control among treatments. The pH values showed no significant differences among control and exeperimental groups.