Milk and dairy products consists a part of the nutrition pyramid . Dairy products may be contaminated with various bacteria and fungi. Investigation has demonstrated that the contamination in traditionally processed yoghurts were higher than industrially processed ones. The main purpose of this review was to collect data from studies on microbial quality of probiotic and non-probiotic yoghurts. Data reported adverse bacteria that can cause damage for dairy products contain gram negative psychrotrophs and coli-forms. Existence of yeasts and molds in industrial yoghurt is indicative of poor hygienic practices in manufacturing and packaging. Aflatoxins are a group of very toxic metabolites of fungi produced through toxicogenic strains of Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius in an extensive variety of agricultural commodities. Aflatoxin B1 is the most frequent produced mycotoxin in contaminated yoghurt. There is a direct relationship between the AFM1 presence in milk and the risk of illness in consumers. Accordingly, it is important to notify producers and consumers about the contamination of yoghurts in order to reduce their potential health hazard and economic losses. With respect to the safety and health effects of yoghurt, it is recommended to consume the industrial yoghurts.
Keywords: Industrial, Microbial quality, probiotic, Traditional, Yoghurt