Efficient milking hygiene reduces bacterial spore contamination in milk

Area of Science:

• Dairy Science
• Food Microbiology
• Animal Hygiene

Background:

• Clostridia spores in milk cause late blowing, a significant cheese defect.
• Spore contamination originates from farm environments and cow feed, entering milk via fecal matter.
• Controlling anaerobic spore-forming bacteria is essential for raw milk cheese quality.

Purpose of the Study:

• To evaluate the impact of different in-parlour milking practices on milk's anaerobic spore-forming bacteria content.
• To monitor variations in spore contamination within cow feed and the farm environment.
• To assess the efficacy of teat preparation routines in reducing bacterial load.

Main Methods:

• Conducted a two-year experimental study with three distinct milking routines: forestripping (F), forestripping and post-dipping (F+Post), and pre-dipping, wiping, forestripping, and post-dipping (Pre+F+Post).
• Collected teat skin swabs, feed, fecal, bedding, and milk samples for microbiological analysis.
• Analyzed clostridial spore contamination levels and standard plate counts in milk.

Main Results:

• Maize silage, a common forage, exhibited the highest clostridial spore contamination.
• Pre-dipping with a detergent/emollient solution and drying significantly reduced teat (1.30 vs. 2.20 log10 MPN/swab) and milk (1.82 vs. 2.47 log10 MPN/L) spore contamination compared to forestripping alone.
• The Pre+F+Post routine resulted in significantly lower standard plate counts (3.80 vs. 4.51 log10 CFU/mL) than the F routine, without affecting beneficial lactic acid bacteria.

Conclusions:

• In-parlour teat preparation, specifically pre-dipping and wiping, is highly effective in minimizing clostridial spore contamination in milk.
• This improved hygiene practice contributes to better milk quality by reducing bacterial load.
• The findings support the adoption of enhanced teat preparation protocols to prevent cheese defects and maintain raw milk quality.