Detection of classical enterotoxins of Staphylococcus aureus in raw sheep, goat, camel, and water buffalo milk by ELISA method

Abstract

Milk is considered a nutritious food because it contains several important nutrients including proteins and vitamins. Conversely, it can be a vehicle for several pathogenic bacteria such as Staphylococcus aureus. The aim of the present study was to investigate the presence of classical enterotoxins of S. aureus in raw milk in Iran. For this purpose, from January 2011 to October 2011, a total of 88 raw milk samples from sheep (n = 28), goat (n = 27), camel (n = 14), and water buffalo (n = 19) were collected from 64 randomly selected herds in Isfahan, Chaharmahal va Bakhtiari, and Khuzestan provinces, Iran, and tested for staphylococcal enterotoxins (SEs) presence by enzyme-linked immunosorbent assay method. Out of 88 samples studied, 11 samples (12.5%) were positive for at least one SE. The prevalence rate of SEs contamination in raw sheep, goat, and water buffalo milk samples were 10.7%, 18.5%, and 15.8%. No classical SEs was founded from raw camel milk samples. Of these, four were positive for staphylococcal enterotoxin A (SEA), four for SEC, two SEA and SEC, and one for SEA and SED. None of the samples was positive for SEB and SEE. Statistical evaluation showed that there were no significant differences (P > 0.05) between the presence of SEs raw sheep, goat, and water buffalo milk samples tested. The quality of Iranian milk is still low, and efforts from the government and the entire productive chain are required to attain consumer safety.