The Diversity Analysis Of Dominant Spoilage Microbial Flora And The Prediction Of Shelf Life In Fresh-cut Cabbage During Storage

Fresh cabbage is not only rich in folic acid, vitamins, dietary fiber, minerals, and rather little of fat and calories, but also has the unusual nutritional therapy health care function. Fresh cabbage used as raw material is processed into fresh-cut cabbage. But in the processing, transportation and storage, rapid growth and reproduction of corruption caused by microorganisms is one of the most important factors affecting shelf life. Mathematical model monitoring the shelf life of fresh-cut products is one of the effective measures to improve the level of product safety, most of the fresh-cut cabbage study focused on pathogens, there is very little research related to spoilage organisms at present. The study analysis on surface microbial species of fresh cabbage for raw materials which was purchased from farm produce market in Ya’an, Sichuan; fresh-cut cabbage was self-made in laboratory, storaged under 4,10,25,30℃, then these strains isolated from it, purificated and inoculated, by means of sensory changes, microbial counts, morphology, biochemical experiments and molecular biological identification, ultimately analysis of the dominant spoilage microorganisms. The research was about Stenotrophomonas maltophilia as strains of dominant spoilage bacteria to cause corruption of fresh-cut cabbage for example, which was studied on dynamics and prediction models of shelf life for the actual production and transportation to better know the growth of microorganisms, improving safety and shelf life of products provides a strong theoretical foundation and protection.Research contents are as follows:1、Research on fresh-cut cabbage during storage, sensory indicators and microbial counts were correlated by regression equations; with the extension of storage time, there was a significant negative correlation between them, also the sensory evaluation score is of 20 points or less, the product was corrupted, then the total number of colonies reached 7.6 CFU above;2、Isolated spoie organisms from fresh-cut cabbage storage in different temperature conditions, the results of inoculation and identification as follows:the Stenotrophomonas maltophilia strain storage at different temperatures have been found, and also has a large proportion, the bacteria was isolated from the raw materials, other bacteria did not inhibit its growth at different temperature storage conditions; Enterobacter was undetected only under conditions of 30 ℃, but the Pantoea undetected at 25,30℃ conditions only, probably Stenotrophomonas maltophilia under certain conditions of storage rapid growth, inhibited the growth of Enterobacter; Acinetobacter, Pectobacterium carotovorum, Bacillus amyloliquefaciens, Exiguobacterium, Pseudomonas and Agrobacterium tumefaciens have been found less than 10%, may be different strains adaptability to different temperatures, the speed of growth will be influenced in a certain extent; Alternaria, Rhizopus, Penicillium, Rhodotorula keep the same of previous studies, but Aspergillus niger and Aspergillus have not been reported;3、The objective of this study was to develop a first-order predictive growth model of Stenotrophomonas maltophilia isolated from fresh-cut cabbage, respectively, to establish the Gompertz model and Belehradek root square model, which used for shelf life prediction. The results indicated that the growth dynamics of Stenotrophomonas maltophilia could be well fitted with the Gompertz function. It suggested that microbial growth models established by our research could predict the growth of Stenotrophomonas maltophilia in fresh-cut cabbage stored from 0 to 40℃.