Instructions for the Proper Collection of Milk Directly From the Udder

Accurately identifying mastitis pathogens is an integral part of establishing an effective mastitis control program. Proper aseptic technique is critical for taking quality milk samples and avoiding the introduction of environmental contaminates. The following guidelines serve to assist individuals when taking milk samples directly from the udder. 

Samples should be collected immediately before regular milking, working in a protected area. Wear gloves while sampling and use new, clean towels and swabs for each teat sampled. 

1.      Loose soils should be removed from the animals and udders should be washed, especially under the teats, before allowing cows to enter the sample collection area.

2.      Fore-strip a few streams of milk from the teat and sanitize with a disinfectant (e.g., 25 mg/L of Iodophor or 0.5% Iodine).

3.      Teats should be dried with clean, single service towels.

4.      Teat canals should be disinfected by opening the canal with finger pressure and swabbing with 70% alcohol or isopropyl.  Alternatively, teats can be dipped in an Iodophor teat dip, allowed 10 seconds to disinfect, and then swabbed with a cotton ball to remove excess dip.  Sanitize teats farthest away first and work toward you, finishing with nearest teats.

5.      Sample from the closest teats first and work away from you, finishing with furthest teats.  Remove 2 streams of milk into a separate vessel before collecting samples into sterile containers.  Handle sample containers and caps aseptically.  Do not drop, lie down, touch the inside of, or otherwise contaminate the containers or caps.  If the container becomes contaminated or is suspect, discard it and use another.  Containers should be held at an angle in order to avoid contaminated debris from falling into the collection container.  Sample containers should be labeled appropriately.

6.      Samples should be refrigerated or placed immediately in a sample case with ice and protected from contamination.

7.      Preferably, samples should be transported to the laboratory within 24 hours.