The Impact of Selected Factors on the Survival Rate of Probiotic Bacteria in Natural Bio-yoghurts Made from Cow’s Milk

The paper examines the survival rate of probiotic bacteria in natural cow’s milk bio-yoghurts depending on the pasteurisation variant of raw material and packaging type used. According to FAO/WHO recommendations, the survival rate of probiotic bacteria should not be lower than 106 cfu/ml on the last day of a yoghurt’s expiration date. This probiotic bacteria count constitutes a therapeutic minimum for bio-drinks. The type of packaging applied did not statistically significantly impact the count or the survival rate of probiotic bacteria. The pasteurisation temperature had a statistically significant impact, but only on the survival rate of the B. bifidum genus – the application of a higher temperature favoured the growth of the population of these bacteria. As regards the count of Str. thermophilus, this impact was observed only 12 hours after manufacturing the yoghurt.