Wasserlauf-Pepper Zoe D, Weachock Rachel L, Geary Christina M, Wiedmann Martin, Martin Nicole H
Department of Food Science, Cornell University, Ithaca, NY 14853.
Quality Milk Production Services, Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853.
JDS Commun. 2025 Mar 18;6(3):282-286. doi: 10.3168/jdsc.2024-0734. eCollection 2025 May.
Routine removal of udder hair through singeing or clipping is a farm management practice that is often used with the intention of reducing SCC and mastitis caused by environmental pathogens. Udder hair removal was also recently identified as a factor of importance for the level of bacterial spores in certified organic bulk tank raw milk. Sporeforming bacteria form resistant endospores, or spores, that allow the organisms to survive harsh environmental conditions, including high temperatures, low moisture, exposure to chemicals, and other conditions that would otherwise be lethal to the vegetative cell. Due to this resistance, spores that are present in raw milk can survive processing hurdles used in dairy product manufacturing, germinate into vegetative cells, and ultimately cause spoilage and quality deterioration in dairy products including fluid milk, cheese, and products using dairy powders as ingredients. Therefore, the aim of this study was to determine if udder hair removal through singeing reduces the concentration of bacterial spores in certified organic bulk tank raw milk. Four organic dairy farms that had not routinely removed udder hair were recruited, and bulk tank samples were collected before and after a singeing intervention on all lactating dairy cows contributing to the bulk tank. Raw milk samples, as well as whole milk powder manufactured from the raw milk collected before and after the intervention, were assessed for different groups of dairy relevant bacterial spores. A numerical reduction from before to after intervention was observed in the mean raw milk mesophilic spore count, thermophilic spore count, and butyric acid bacteria most probable number, whereas a numerical increase was observed in the mean raw milk total bacteria count and psychrotolerant spore most probable number, although none of these changes were significant. The mean mesophilic spore count and thermophilic spore count in whole milk powder manufactured from pre- and post-intervention raw milk was, however, significantly reduced from 2.46 to 1.58 log cfu/g and 1.44 to 1.22 log cfu/g, respectively. The results of our study indicate that udder hair removal may aid in reducing key populations of spores found in organic raw milk and resulting dairy powders manufactured from that raw milk, although the small sample size in our study likely affected the significance of our results. Future studies should further investigate the role of udder hair removal on a larger set of organic farms, as well as the downstream impact on spore levels in other manufactured dairy products.
通过烧灼或剪毛常规去除乳房毛发是一种农场管理做法，其使用目的通常是降低由环境病原体引起的体细胞计数（SCC）和乳腺炎。乳房毛发去除最近还被确定为对经认证的有机大罐原料乳中细菌孢子水平具有重要影响的一个因素。产芽孢细菌会形成抗性内生孢子或芽孢，使这些生物体能够在恶劣的环境条件下存活，包括高温、低湿度、接触化学物质以及其他对营养细胞具有致死性的条件。由于这种抗性，原料乳中存在的孢子能够在乳制品制造过程中所用的加工环节中存活下来，萌发成营养细胞，并最终导致包括液态奶、奶酪以及以奶粉为原料的产品在内的乳制品变质和质量下降。因此，本研究的目的是确定通过烧灼去除乳房毛发是否能降低经认证的有机大罐原料乳中细菌孢子的浓度。招募了四个未常规去除乳房毛发的有机奶牛场，并在对所有为大罐提供原料的泌乳奶牛进行烧灼干预前后采集大罐样本。对原料乳样本以及干预前后采集的原料乳制成的全脂奶粉进行了与乳制品相关的不同组细菌孢子的评估。干预前后，原料乳的嗜温孢子计数、嗜热孢子计数和丁酸菌最可能数出现了数值下降，而原料乳的总细菌计数和耐冷孢子最可能数出现了数值上升，不过这些变化均不显著。然而，干预前后原料乳制成的全脂奶粉中的嗜温孢子计数和嗜热孢子计数分别从2.46 log cfu/g显著降至1.58 log cfu/g以及从1.44 log cfu/g显著降至1.22 log cfu/g。我们的研究结果表明，去除乳房毛发可能有助于减少有机原料乳及由该原料乳制成的乳制品粉末中发现的关键孢子种群，尽管我们研究中的样本量较小可能影响了结果的显著性。未来的研究应在更大规模的有机农场中进一步调查去除乳房毛发的作用，以及对其他制成乳制品中孢子水平的下游影响。
