Chemical and Microbial Safety Criteria for Egyptian Ras Cheeses

Abstract

Up until now, most of the Ras cheese has been produced by small dairy sectors in Egypt using raw milk. This research aimed to determine the pathogens, and undesirable microorganisms in traditional Egyptian Ras cheese using classical methods and real-time PCR. Forty samples of Ras cheese were analysed for chemical and microbiological properties. The results revealed a wider range in the chemical composition of the collected samples. Most of the Ras cheese samples were within the Egyptian Standard for chemical compositions. There were only two samples of Ras cheese that had more moisture than the Egyptian Standard recommended.. The results of the microbiological analysis of the Ras cheese reveal that the coliform count ranged between 1 and 5.20 log CFU/g, with an average of 1.70 log CFU/g. Anaerobic spore-forming bacteria (Clostridium perfringens) were found in 29 out of 40 Ras cheese samples. All Egyptian cheese samples contained more yeast and mold than the Egyptian Standard recommends. All cheese samples were free of Listeria monocytogenes and Salmonella spp. The real-time PCR showed that 5% of samples were positive for methicillin-resistant Staphylococcus aureus, and all the analysed samples were free of E. coli O157:H7. According to this study's findings, most Ras cheese samples contained higher levels of Staphylococcus aureus, molds, and yeasts than what Egyptian standards recommended. The results of this study should be used to develop specific procedures for risk management along the milk production chain.