Clostridia, enterobacteriaceae, enterococci and its relation to biogenic amines content in Egyptian marketed ras cheese

ABSTRACT

In this study, 40 samples of Ras cheese were collected and examined for the incidence of Clostridia, Enterobacteriaceae and Enterococci species and detecting their biogenic amines content. 130 isolates were identified and examined for the histamine production. The average count of Clostridia, Enterobacteriaceae and Enterococci were 6 x 102, 7.8 x 102 and 4.4 x 105 CFU/g, respectively. Tyramine, histamine, putrescine, cadaverine, tryptamine and phenylethylamine were detected in 57.5, 100, 42.5, 45, 7.5 and 60% of the examined samples, respectively. Tyramine was observed in most of the cheese samples contaminated with large counts of Streptococcus faecalis [>105 CFU/g]. 25% of the samples contained over 10 mg histamine/100 g cheese. The research discussed the relation between the incidence of Clostridia, Enterococci and Enterobacteriaceae species and the presence of some biogenic amines in Egyptian Ras cheese