The study on the microbial level contamination of butter offered in Tehran in 2007

Microbial contamination of butter out of the range of standard as other food products is a hazard for human health. In this research the microbial level contamination of butter marketed in north, centre and south of Tehran were studied. In this study, the existence of Coliforms, Escherichia coli, Staphylococus aureus,Psychrotrophic bacteria and moulds in 48 samples of packed butter, collected from markets in three area of north, centre and south of Tehran were tested and measured according to the examination of Standard Institute of Iran. Of 41 butter samples, 31 (64.58%) were out of the acceptable level of the microbial contamination.The number of contaminated samples in north, centre and south of Tehran were as 9 (29%), 11 (35.5%) and 11(35.5%) respectively. The results of confirmation and IMViC tests of fecal Coliforms showed contamination of eight samples (16.66%) to E. coli, five samples (16.12%) to Citrobacter spp. and 18 samples (58.06%) to Enterobacter spp. Staphylococus aureus contamination was not observed in any samples. Besides, statistical analysis indicated that psychrotrophic bacteria were not out of the range of standard in any of samples. Three samples (6.25%) were contaminated to moulds that one and two samples were from centre and south of Tehran respectively. The significant number of butter samples contained coliforms, which definitely are not suitable for consumption. More attention is needed to hygienic control of factories related to dairy products for food safety in the community.