Investigation On Biogenic Amine Production Of Enterobacter Aerogenes And Enterobacter Cloacae

The traditional chinese fermented sausage is one of the spontaneously fermented sausages, consumers love it because of its unique flavor. Biogenic amine, recognized as one of the potentially harmful substance threaten to human health, its widely presence in fermented sausages have already become the important factor affecting the quality and safety of fermented sausages. Biogenic amines are mainly produced by decarboxylation reaction of bacterial amino-acid decarboxylases, therefore the study on formation mechanism of biogenic amines by microorganisms could be an important approach to solve the biogenic amines problem. Enterobacter aerogenes and Enterobacter cloacae have been reported as biogenic amine producing bacteria in many essays, as our prophase study showed that they were two dominant bacteria responsable for cadaverine and putrescine in traditional chinese fermented sausage, and there may have an interaction between them when they were cultivated together. Reports on their growth and biogenic amine producing abilities are sparing, but there are no reports aimed on their interaction to the beat of my knowledge. So in this reseach, the standard strains of Enterobacter aerogenes and Enterobacter cloacae were cultivated in tube and sausage seprarately in diffenrent ratio to study their interaction on growth and biogenic amine producing abilities. Our results stated as follows:1. Marking Enterobacter aerogenes and Enterobacter cloacae with RFP and GFP GenesIn this reseach, the plasmid pJZ402with red fluorescent protein(RFP) or the plasmid pJZ383with green fluorescent protein(GFP) was transferred into Enterobacter aerogenes or Enterobacter cloacae, obtained two marked strains who could transfer and express the foreign genes stably, they were named as EABR and ECBG The fluorescent of culture would be used to evaluate the bacteria counts.2. Investigation on biogenic amines production of Enterobacter aerogenes and Enterobacter cloacae in tubeIn this study, we cultured Enterobacter aerogenes and Enterobacter cloacae by different ad rationem in tubes. The pH value, bacteria content, cadaverine and putrescine concentration were detected every4hours during the48h’s cultivation. The results showed that:the interaction of bacteria growth and biogenic amine production between Enterobacter aerogenes and Enterobacter cloacae was notable. When their inoculation ratio was equal, the growth rate of Enterobacter aerogenes was remarkably higher than other treatment, but the growth rate of Enterobacter cloacae and the total bacterial content were unchanged. In the aspect of biogenic amine production, Enterobacter aerogenes and Enterobacter cloacae both produced cadaverine and putrescine at the same time, Enterobacter aerogenes had stronger ability to produce cadaverine and Enterobacter cloacae had stronger ability to produce putrescine; the mixed inoculation could strengthen their cadaverine-producing abilities, but the production of putresine had no significant different.3. Investigation on biogenic amines production of Enterobacter aerogenes and Enterobacter cloacae in traditional chinese fermented sausageIn this study, we used different ad rationem mixture of Enterobacter aerogenes and Enterobacter cloacae as starter culture to make traditional chinese fermented sausage, the pH value,bacteria population and biogenic amine production were detected during the fermentation and ripening period, the results showed that:there was an interaction between Enterobacter aerogenes and Enterobacter cloacae in traditional chinese fermented sausages, but this interaction was not the same as it was in tube test. Enterobacter cloacae both produced cadaverine and putrescine at the same time, Enterobacter aerogenes had stronger ability to produce cadaverine, meanwhile its putrescine-producing ability wasn’t weak, sometimes it was stronger than Enterobacter cloacae; When their inoculation ratio was equal, not only their bacteria growth but also their cadaverine and putrescine production were increased, namely they had the synergistic effects on bacteria growth and biogenic amine production.