Introduction and objective:
The major sources of bacterial contamination of raw milk are post-harvest manipulation; therefore the disinfection of teat and teat cups which decrease the bacterial load has a positive impact on minimizing new infection rates. The aim of the study was determination of the incidence of pathogens on investigated surfaces, evaluation of the effectiveness of sanitation regime in the reduction of surface microbial load, and determination of the effectiveness of mechanical cleaning of teats in a milking parlour for dairy cows.

Material and methods:
Samples from surfaces were taken by microbiological swabs using a sterile cotton swab from area of 5×2 cm2. Sanitation regime was evaluated based on the effectiveness of active substances – lactic acid and sodium hypochlorite.

From a total of 105 swab, 44 samples were found positive for Staphylococcus aureus, 16 samples for E. coli, 15 samples for Micrococcus spp., 8 samples for Staphylococcus xylosus, 9 samples for Staphylococcus cohni urealyticum, 1 sample for Enterococcus faecalis. Among isolates, S. aureus was the predominat species from teats – 19/45, teat cups, 15/45 and from wiping cloths 10/15. Sanitation regime was confirmed by a decrease in the number of coliform bacteria (CB) determined on teat and teat cups from 2.33–0.95 Log10 CFU/cm2 (p<0.001) and 0.90–0.62 Log10 CFU/cm2 (p<0.001), respectively, and in the number of total bacteria count (TBC) determined on teat and teat cups from 4.36–0.99 Log10CFU/cm2 (p<0.001), and 1.85–0.77 Log10 CFU/cm2 (p<0.001), respectively. Incidence of CB (2.53 Log10 CFU/cm2) and TBC (3.83 Log10 CFU/cm2) on wiping cloths after mechanical cleaning of udders stress the importance of this step.

Results show that disinfectant with lactic acid as the main active ingredient is suitable for bacterial reduction. Post-milking disinfection of teat and teat cups reduces bacterial contamination and proves to be most effective against environmental bacteria.

This work was supported by grants VEGA 1-0162-23: Reduction of antibiotic use in dairy mastitis control programs and SAIA 2022-05-15-001: The effect of udder pathogens on the production and degree of oxidative stress in dairy cows.
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