Krasnikova E S, Larionova O S, Krasnikov A V, Kazieva G Kh
Saratov State Agrarian University named after N.I. Vavilov.
Vopr Pitan. 2018;87(4):48-55. doi: 10.24411/0042-8833-2018-10041. Epub 2018 Jul 13.
The questions of quality control and safety of milk raw materials has always been relevant for the dairy industry. One of the most common cattle infection is bovine leukemia (causative agent - BLV), which often occurs in conjunction with a closely related infection -bovine immunodeficiency (causative agent - BIV). These retroviruses are considered to be species-specific, so the key issue for the dairy industry is the nutritional and raw value of milk of infected cows (without clinical signs). Milk of infected with leukemia cows has changed physical and chemical properties and microbiological parameters, but it is allowed to be processed after a single pasteurization. Thus, there is a possibility of getting of the infected with retroviruses cow's milk into the bulk milk, which can affect the quality of the processed products. Characteristics of BlV-positive cow's milk have not yet been studied. The aim of the research was the study of influence of BLV- and BLV- BIV-infected cows' milk impurities (10, 30 и 50%) on organoleptic, physicochemical and microbiological parameters of produced kefir drink. It is revealed that with increasing the mass fraction of infected with retroviruses cows' milk, acidity of composite samples increased of 1-3 °T and total viable bacteria's count rose by 1-3 orders of magnitude, while the total protein in milk decreased by 0.05-0.95% contrasted with an increasing of milk fat content by 0.3-0.9%. However, these characteristics were within normal limits. In samples containing 50% of milk infected with retroviruses cows, coliforms were detected in 0.1 ml, and the rate of total viable bacteria's count exceeded the permissible limits. Therefore, microbiological characteristics are determination markers of dairy raw materials with the high content of milk of the infected with retroviruses cows. The kefir drink was produced from pasteurized samples. It was found that the acidity of the product was lower by 1-10 °T, while the processing time increased by 4-50%, correlating with the mass fraction of infected with retroviruses cows' milk, compared to control. When the mass fraction of infected with retroviruses cows' milk was 30 and 50%, the processed product had a heterogeneous consistency with flake clots. At the same time, the lactic-acid-producing bacterium count in kefir drink decreased by 2-3 orders, and mold and coliforms were found in it. Thus, the presence more than 10% of milk from infected with retroviruses cows in raw materials leads to a decrease in its technological properties, and dose 30 and 50% leads to non-compliance of the processed product with hygienic standards.
牛奶原料的质量控制和安全问题一直是乳制品行业关注的重点。牛白血病（病原体为BLV）是最常见的牛类感染疾病之一，它常与一种密切相关的感染——牛免疫缺陷病（病原体为BIV）同时发生。这些逆转录病毒被认为具有种属特异性，因此乳制品行业面临的关键问题是感染奶牛（无临床症状）所产牛奶的营养和原料价值。感染白血病的奶牛所产牛奶的物理化学性质和微生物参数发生了变化，但经过一次巴氏杀菌后仍可用于加工。因此，存在感染逆转录病毒的奶牛所产牛奶混入原料奶中的可能性，这可能会影响加工产品的质量。目前尚未对BIV阳性奶牛所产牛奶的特性进行研究。本研究的目的是研究感染BLV和BLV - BIV的奶牛所产牛奶杂质（10%、30%和50%）对所生产的开菲尔饮品的感官、物理化学和微生物参数的影响。研究发现，随着感染逆转录病毒的奶牛所产牛奶质量分数的增加，复合样品的酸度升高了1 - 3°T，总活菌数增加了1 - 3个数量级，而牛奶中的总蛋白含量下降了0.05 - 0.95%，同时乳脂含量增加了0.3 - 0.9%。然而，这些特性仍在正常范围内。在含有50%感染逆转录病毒的奶牛所产牛奶的样品中，每0.1 ml检测到大肠菌群，总活菌数超过了允许限度。因此，微生物特性是含有高比例感染逆转录病毒的奶牛所产牛奶的乳制品原料的判定指标。开菲尔饮品由巴氏杀菌后的样品制成。结果发现，与对照组相比，产品的酸度降低了1 - 10°T，而加工时间增加了4 - 50%，这与感染逆转录病毒的奶牛所产牛奶的质量分数相关。当感染逆转录病毒的奶牛所产牛奶质量分数为30%和50%时，加工后的产品质地不均匀，有片状凝块。同时，开菲尔饮品中产乳酸菌数量减少了2 - 3个数量级，并且检测到霉菌和大肠菌群。因此，原料中感染逆转录病毒的奶牛所产牛奶比例超过10%会导致其工艺性能下降，比例为30%和50%时会导致加工后的产品不符合卫生标准。
