Physicochemical and Microbiological Characteristics of Traditional Yogurts Produced by Nomads in Khorasan-e-Razavi
Subject Areas : Food Microbial Contamination
mohamad
habibi
1
(گروه علوم و صنایع غذایی دانشگاه فردوسی مشهد)
reza
farimani
2
(گروه علوم و صنایع غذایی دانشگاه شهید باهنر کرمان)
sedigheh
fazli
3
(.دانشکده داروسازی، دانشگاه علوم پزشکی)
Keywords: Staphylococcus aureus, acidity, Escherichia coli, pH, nomads, coliform, Traditional yogurt, fat content,
Abstract :
Yogurt is one of the most popular types of fermented milk almost all over the world particularly the Middle East. However, due to poor sanitary conditions of milking and storage, improper heat treatment, and secondary contamination, milk is a good media for transmission of a broad range of pathogens. The aim of this study was to examine health and chemical properties of artisanal yogurt produced by nomads. Samples were collected from nomadic regions in Khorasan-e-Razavi Province. The viable count of coliform, E.coli, coagulase-positive staphylococci (Staphylococcus aureus), yeast and molds, lactic acid bacteria and chemical properties (pH, acidity, fat and total solid) were determined. Most probable number (MPN) technique showed that only one yogurt sample prepared with raw milk exposed to low heat treatment (40 °C) was contaminated with 2/4 × 102 CFU/g coliform and was E. coli positive. No Staphylococcus aureus were found in all examined samples. High counts of Yeast and molds in some samples revealed unsatisfactory sanitary conditions during fermentation and post production. PH of yogurt samples was in the range of 3.8 - 4.3 and the acidity was between 1.3 – 2%. The fat content of yogurt samples was varied between 0.5 to 45%. It is concluded that above mentioned products were considered containing health risks. Authorities should pay more attention and supervision focused on improving health conditions for production of such dairy product. This survey is the first reported case about production of a yogurt with raw milk in Iran.
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