Sampling Detection Of Several Kinds Of Food In Hubei Province And Research On The Change Rule Of Nitrite In Pickles

This paper is about sampling and determinating the content of additives in food in Hubei Province, in order to evaluate food safety in Hubei Province. The research object is the nitrite in pickle. Through studying nitrite, nitrate, microbial number (mainly in bacteria, lactic acid bacteria, intestinal tuberculosis) and pH in pickle of natural fermentation and the inoculated fermentation, the aim is to research the change rule of nitrite in the process of making the pickle.Sampling and determinating the content of benzoyl peroxide in flour, sodium nitrite in pickles and duck neck, and sodium formaldehyde sulfoxylate in rice noodles. The experiment found that the content of benzoyl peroxide in majority flour is lower than60mg/kg which is the national standard, but the content of benzoyl peroxide exceed the standard. The contents of nitrite in pickled vegetables are all below8mg/kg, and the national standard is20mg/kg. The contents of nitrite in duck neck are all below5mg/kg, and the national standard is30mg/kg. All the rice noodles do not contain sodium formaldehyde sulfoxylate, because only detect formaldehyde, no sodium bisufite.The paper has studied that temperature, salt concentration and the vinegar effect on the content of nitrite in pickle during natural fermentation, the change of number of bacteria, lactic acid bacteria, Enterobacteriaceae, and pH value. The research found that at26℃,5%salt concentration,0.6%vinegar is most beneficial for vegetable fermentation..During natural fermentation, the change trend of number of lactic acid bacteria and bacterial are consistent with nitrite which increase after the first drop and reach the maximum value in the third day. The content of nitrate content, the number of Enterobacteriaceae and pH has been reduced. During inoculated fermentation, the content of Nitrite was in a lower stat and no nitrite peak, the number of lactic acid bacteria increased after the first drop. The content of nitrate, pH value, and the number of bacteria andente robacteriaceae has been reduced in the whole process. The number of bacteria and Enterobacteriaceae were less in initial stage of the inoculated fermentation, which was not detected in the third day when the pH was below4.0.The change tendency of pH and number of microbial are consistent with content of nitrite indicates the bacteria affect nitrite formation as the main factor in fermentation. In the initial stage of fermentation, bacteria blooms make the reduction of nitrate to nitrite, which cause the appearance of the nitrite peak. In the fermentation stage, the lactic acid bacteria degradation reduce the content of nitrite.