Forty five of retailed sausage samples (including fresh, frozen and fermented sausage) were collected from local and central markets of Qalubia, Cairo and Giza Governorates and analyzed for some microbial groups enumeration, pathogens detection and chemical characteristics. Data showed that, all sausage types contained coliform microorganisms where frozen sausage had coliform counts over the permissible limits followed by fresh and fermented sausage. On the other hand, fermented sausage had the highest records of lactic acid bacteria, proteolytic and lipolytic bacteria. All samples were positive for presence of Staph. aureus especially fresh sausage which recorded the highest mean counts. Listeria monocytogenes, E. coli O157:H7 and Salmonella spp. were also presented at higher percentage in fresh sausage followed by frozen and fermented ones. Concerning chemical analysis, frozen sausage had the highest values of sodium nitrite and total volatile nitrogen while, the highest mean values of thiobarbaturic acid was observed in fermented one. Furthermore, antimicrobial activity of eight essential oils of spices and two strains of lactic acid bacteria against four strains of foodborne pathogens isolated and identified from the previous three types of sausage was studied. Maximum mean values of inhibition zones of spices against the tested pathogens were obtained by marjoram followed by cumin and mint essential oils. In addition, all tested pathogens were inhibited by either Lactococcus lactis or Lactobacillus plantarum and their mixture which gave the highest mean values of inhibition zones.
Key words: Sausage, coliform bacteria, Staph. aureus, E. coli O157:H7, Salmonella
Sp., L. monocytogenes, sodium nitrite, spices, lactic acid bacteria. |
