Effect of Acidification Treatment on Milk Quality and Microbial Community of Milk Replacer Powders
This passage investigates the impact of acidification on the quality and microbial community of substitute milk powder.The experiment consisted of two groups:a control group and an acidification-treated group,each with 8 replicates.The acidified milk group adjusted the milk pH to 4.0～4.5 using an acidifying agent.After preparing the milk in both groups,samples were taken at 12,24,and 48 hours of room temperature storage.The composition of the milk and microbial community were analyzed using 16S rRNA gene sequencing.Results indicates:(1)At 12 hours,acidified milk had significantly lower lactose and milk fat compared to the control group(P<0.05),while protein content was significantly higher(P<0.05).At 24 hours,acidified milk showed lower milk fat and non-fat solids content compared to the control group(P<0.05).By 48 hours,acidified milk had lower lactose,milk fat,and non-fat solids content than the control group(P<0.05).Over time,both groups experienced a decrease in lactose,milk fat,and non-fat solids content(P<0.05),while protein content increased(P<0.05).The pH values of both milk groups decreased with extended storage time(P<0.05).(2)At the same time points,the acidified milk exhibited significantly higher alpha diversity indices,including Chao1,ACE,Shannon,and Simpson indices,compared to the control group(P<0.05).Principal component analysis revealed significant differences in bacterial community structures between the acidified milk and control groups at each time point(P<0.05).Across all time intervals,the relative abundances of Bacteroidetes,Deinococcus-Thermus,and Actinobacteria were consistently higher in the acidified milk group than the control group(P<0.05).The relative abundance of Proteobacteria significantly increased over time in the control group(P<0.05),while in the acidified milk group,it significantly decreased(P<0.05).Beneficial genera such as Streptococcus,Lactococcus,Lactobacillus,and Anoxybacillus were more abundant at each time point in the acidified milk group than the control group(P<0.05),whereas genera like Bacillus,Pantoea,and Enterococcus were less abundant(P<0.05).In summary,acidification treatment of substitute milk powder altered the microbial community structure,increased the relative abundance of beneficial genera,decreased the abundance of harmful bacteria,and effectively preserved the nutritional components in the milk.
Milk replacerAcidified milkMilk qualityMicrobial community
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