Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Fruits, vegetables,nuts processing industry > Basic science

Studies on the Isolation, Identification and Characteristics of Spoilage Microbes from Mustard Tubers

Author JiangGaoQiang
Tutor ChenJianChu
School Zhejiang University
Course Of Food Science
Keywords Tuber mustard isolation identification characteristic microbes
CLC TS255.1
Type Master's thesis
Year 2006
Downloads 486
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Tuber mustard are made of greengrocery, which are pickled with some seasoning matters, by worked on a series of biochemistry reactions, such as the high osmotic pressure of salt, ferment by microorganisms and decomposition of protein. Tuber mustard are convenience, nutrient and delicious. Nowadays, the consumption of tuber mustard will expand quickly with the economy developed.Tuber mustard are usually contaminated by microorganisms through all of the taches of consumption, including purchase, transport, processing and store. Microbe corruption is the most important factor that causes Tuber mustard degenerative. The object of this study is to make sure the microbes that induced tuber mustard corruption. In this paper, the spoilage microbes that caused tuber mustard corrupted were isolated and identified. The characteristics of putrescent microbes were studied. Also, microorganisms of some tuber mustard in the market at Hangzhou were analyzed. Main results are as following:1.Seven bacterium fungus and four microzyme fungus were isolated from tuber mustard by plate counting. It showed that two bacteria fungus will induce tuber mustard corruption in counterevidence experiments. Two fungus were identified by a series of experiments which include observing morphological characteristics, dyeing, physiological & biochemistry reactions and so on. It is showed that the two fungus were Bacillus firmus and Bacillus cereus.2. According to the principle of turbidimetric method, with regarding the absorbency value of bacteria as the standard of bacteria growth, which lived in liquid culture medium, Growing curve, heat-resistance, salt-resistance and nitrate-resistance of Bacillus firmus and Bacillus cereus were studied here. It was showed that the growing-speeds of Bacillus cereus is more quick than Bacillus firmus, but the logarithmic phase is more or less beween them;low-temperature(<10℃)and high-salt(>12%) can restrain the two spoilage microbes effectively;and there is no relation between nitrite and the two spoilage microbes.3.A lot of job has been done about determination of Escherichia Coli, totalnumber of bacterial colony, acid producing bacteria, yeast and molds of tuber mustard that pot-packing or bag-packing in Hangzhou market. It showed that the microbe radices of pot-packing was more than bag-packing. Vacuum-packing can prevent tuber mustard from contaminating.4. Changes of the content of protein, amino acid, deoxidize sugar, total acid in two different tuber mustard which have 6% and 11% salt concentration has been mensurated respectively. Showed that the salt can change the favor by change the phys-chemical character of tuber mustard.

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