Investigation of the microbial quality and the occurrence of Shiga-like-toxin-producingEscherichia coliand methicillin resistantStaphylococcus aureusin traditional cheeses produced in northwest of Iran

Abstract

PurposeThis paper aims to evaluate the microbial quality of some traditional cheese samples (sheep, cow and koopeh cheeses) consumed in northwest of Iran, and to detect Shiga-like-toxin-producingEscherichia coli(STEC) and methicillin-resistantStaphylococcus aureus(MRSA) in cheese samples by polymerase chain reaction (PCR) method.Design/methodology/approachAlmost half of the project was based on counting the population of Staphylococcus aureus, total coliforms, Escherichia coli, and total aerobic mesophilic bacteria, also the other section was related to the isolation and the detection of the STEC and MRSA in cheese samples. The findings were compared with standard maximum and threshold values.FindingsThe results revealed that 36.99, 30.14 and 100% of cheeses exceeded the standard threshold value ofE. coli(102), total coliforms (104) andS. aureus(102). However, total coliforms, in any of the cheese samples examined, did not reach the maximum value and only 24.66% of samples exceeded the maximum value ofE. coli. Also, no significant difference (p> 0.05) in counts of each bacterial group examined in sheep, cow and koopeh cheeses was observed. The colony PCR method demonstrated the existence of 19 MRSA and 2 STEC isolates.Originality/valueThis research showed a general overview of the bacterial quality of cheeses in northwest of Iran.