Cellular and soluble components decrease the viable pathogen counts in milk from dairy cows with subclinical mastitis

Area of Science:

• Veterinary Medicine
• Microbiology
• Dairy Science

Background:

• Subclinical mastitis in dairy cows impacts milk quality and safety.
• Understanding pathogen reduction mechanisms in preserved milk is crucial.

Purpose of the Study:

• To identify factors reducing viable pathogen counts in milk from subclinically mastitic cows during preservation.
• To differentiate the roles of somatic cells and antimicrobial peptides in pathogen reduction.

Main Methods:

• Milk samples from subclinically mastitic cows were centrifuged to separate somatic cells and soluble components.
• Fractions were incubated with bacteria, and viable bacterial counts were assessed before and after incubation.
• Incubation occurred at 15-25°C for 5 hours.

Main Results:

• No viable bacteria were found in 28.8% of samples initially.
• After 5-hour incubation with cellular components, 48.1% of samples showed no viable bacteria.
• Soluble components did not significantly reduce bacterial counts, with some pathogens increasing.
• Cellular components significantly reduced bacterial and yeast counts, though not always statistically significant.

Conclusions:

• Both cellular and soluble components in high somatic cell count milk contribute to pathogen reduction during preservation.
• Somatic cells are particularly effective in reducing bacterial load in milk.
• Further research may optimize preservation strategies using these milk components.