Microbiological Quality of Domiati Cheese and the Influence of Probiotics on the Behavior of Staphylococcus aureus and Escherichia coli O157:H7 in Domiati Cheese

Abstract

AbstractThe objectives of this study were to assess the microbiological quality of domiati cheese and to evaluate the capacity of Lactobacillus acidophilus La‐5 and Bifidobacterium longum ATCC15707 to inhibit the growth of Staphylococcus aureus and Escherichia coli O157:H7 during manufacture and storage of domiati cheese. The results of the microbial investigation indicated poor microbiological quality of cheese samples, the microbiological parameters recorded higher values than admissible levels. Domiati cheese produced from milk artificially contaminated with S. aureus and E. coli O157:H7 was used as a model for studying the antibacterial activity of L. acidophilus La‐5 and B. longum ATCC15707 against these pathogens. The results obtained in this study indicated the remarkable effect of L. acidophilus La‐5 and B. longum ATCC15707 in preventing survival of S. aureus and E. coli O157:H7 during cheese storage. The inactivation rate was more pronounced with S. aureus than E. coli O157:H7 and it was dependent on probiotic strain. L. acidophilus inactivation was significantly higher (P value < 0.05) than that attained with B. longum. Survival of probiotic bacteria in domiati cheese was satisfactory.Practical ApplicationsThe microbial contamination of domiati cheese represents not only spoilage of the product but also constitutes a high risk to human health. The probiotic bacteria have the ability to improve the microbiological quality and safety of domiati cheese. Survival of both Lactobacillus acidophilus La‐5 and Bifidobacterium longum ATCC15707 in domiati cheese was satisfactory, which indicate that the domiati cheese would be a suitable vehicle for the delivery of probiotic bacteria.