Our Milk Testing Protocols

First thing’s first: I need to apologize for the delay in making this post. Earlier this year I wrote about the importance of sanitation and testing when it comes to raw milk, and then I never got around to writing about what we do on our farm.

Let’s talk about sanitation!

  • We use a closed milking system to prevent dirt, hair, feces, and insects from contaminating our milk. 
  • During milking, we wear gloves, use teat dip, and use a clean towel to wipe each goat’s teats.
  • After milking, we bottle and chill milk immediately. Milk is poured in our clean kitchen, into glass bottles that have been sanitized with diluted bleach.
  • We wash all of our milking equipment with soap and hot water, followed by an acid rinse, after every use.
  • We soak all of the critical components of our milking system in diluted bleach after every use.
  • We regularly clean our goat’s pens so that they’re always laying on clean bedding. This helps to prevent mastitis as well as fecal contamination from dirty animals.

I’ve spent the past few months brainstorming the best ways to aggregate and present all of our milk test data. We run standard plate counts and Coliform/E. coli tests on a bi-weekly basis. I decided that, for simplicity’s sake, I am going to make available the averages for each test that we run. The numbers for the current year are a rolling average, updated in real time: Milk Test Averages

So what do these numbers mean?

The standard plate count (or aerobic plate count) is a quantifies the amount of bacteria in our milk. This test counts both beneficial and potentially harmful bacteria. Although the state limit is 30,000/mL, we aim to keep the overall bacteria level of our milk under 1,000 cfu/mL to reduce the likelihood that harmful bacteria may be present.

A Coliform count lower than 10 cfu/mL is indicative of excellent sanitation. While we always strive for excellence, our average may not fall below 10 this year, as we had a few slightly elevated Coliform counts at the beginning of the milking season. We’ve since made adjustments to our sanitation procedures to meet our goal. 2020 is our first year testing and selling milk, so we are still learning!

We also use a weekly CMT (California Mastitis Test) to monitor the SCC (somatic cell count) of each of our does throughout her lactation. An elevated SCC indicates the presence of mastitis (an infection of the mammary glands). If one of our goats tests positive, we can immediately begin milking her separately and discarding her milk until we are certain that the infection has cleared.

It is possible to test for specific pathogens, such as Salmonella, Campylobacter, and Listeria. However, doing so is usually unnecessary so long as the APC and Coliform counts are consistently low.

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