title: Occurrence of Noroviruses and Their Correlation with Microbial Indicators in Raw Milk.
abstract: This study was conducted to investigate the microbiological quality of raw cow's milk in a collection center in the city of Mashhad, Iran. A total of 19 raw cow's milk samples were collected and simultaneously analyzed for male-specific (F(+)) coliphage and Escherichia coli using culture-based methods and for enteric viruses by reverse transcriptase semi-nested PCR using primer sets specific for human norovirus Group I (HNV-GI), human norovirus Group II (HNV-GII), and enteroviruses (EV). Seven out of 19 (36.8%) raw milk samples tested positive for human noroviruses (HNV). The genotypes detected were HNV-GI and HNV-GII. Three positive samples contained both genotypes, and 2 samples were positive for either of HNV-GI and HNV-GII. No sample tested positive for EV. The correlation between the occurrence of HNV and the microbial indicators was studied. The statistical analysis using first- and second-order regression revealed that there is no correlation between F(+) coliphage and E. coli. Similarly, no correlation was noticed between the occurrence of F(+) coliphages and HNV. However, frequency distribution analysis indicated that 3 out of 4 (75%) of raw milk samples containing F(+) coliphage at a concentration higher than 10(4) pfu/100 ml were also positive for noroviruses. The limited data on the occurrence of noroviruses in raw milk suggest a poor sanitation and hygiene practices at the facility and indicate a possible correlation between the viral indicator at high concentration and human noroviruses; however, this analysis needs further investigation in a larger scale study.
authors: Department of Food Science & Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran, yavarmanesh@um.ac.ir.
authors: Masoud
authors: M
authors: Yavarmanesh
authors: Absar
authors: A
authors: Alum
authors: Morteza
authors: M
authors: Abbaszadegan
mesh_terms: D000818:Animals; D002417:Cattle; D003090:Coliphages / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification* / Q000821:virology; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000295:instrumentation; D005838:Genotype; D006801:Humans; D007492:Iran; D008297:Male; D008892:Milk / Q000382:microbiology* / Q000821:virology*; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers