Editor’s note: The author is the lab director at Bob-White Systems Lab in Royalton, Vermont. He also owns and operates a pasture-based beef and lamb farm with his family. They milk two cows and a goat for their household.

One big benefit of running a FDA-certified dairy lab is that we get to see what works and what doesn’t work to keep milk clean. “Clean,” for our purposes, means that it passes Vermont’s Tier II Raw Milk Standards, which happen to be some of the most stringent in the country, more so than federally regulated pasteurized milk standards.

At the lab we perform FDA-certified testing to ensure raw milk producers are compliant with Vermont’s standards. We also perform non-FDA-certified tests for diagnostic services. That means we see all kinds of milk, with all kinds of problems, and we help producers troubleshoot many different issues.

Vermont’s Tier II Raw Milk Standards require that raw milk intended for retail sale pass four tests; total bacteria count below 15,000 cfu per ml, coliform count below 10 cfu per ml, somatic cell count below 225,000 per ml (500,000 per ml for goats), and no antibiotic residue found. “Cfu per ml” stands for colony-forming units per milliliter; bacteria form colonies, and this is the number of colonies per milliliter of milk.

Antibiotic residue looks for traces of cow penicillin or other antibiotics that could affect people with antibiotic allergies and probably contribute to the creation of the notorious MRSA and other antibiotic-resistant bacteria. Every state has its own set of regulations and laws regarding raw milk; more info can be found at the Farm to Consumer Legal Defense Fund. (Click here to see the map.)


Federally regulated, commodity raw milk for pasteurization must have a total bacteria count less than 100,000 cfu per ml and a somatic cell count less than 750,000 per ml (1,000,000 per ml for goats). Pasteurized milk must have less than 20,000 cfu per ml of bacteria, 10 cfu per ml of coliform and no requirement on somatic cell count. (They don’t increase after leaving the cow.)

A high count only means the milk was produced and handled in a way that could support harmful pathogens were they present. In other words, if harmful bacteria were to enter your production practice, it could flourish, but it might not be there at all. These test standards are the tools we currently have to assess milk safety, so that’s what we’re going to use.

Animal health for clean, raw milk

With that background in mind, we’ve pulled together a few basic guidelines that will help you produce “clean” milk on your dairy. We begin with the animals.

Start with healthy animals

Imprecise as the tests may be, they can still help you to find a healthy animal. High counts on any of those regulated tests will tell you that something is wrong. In addition, the lab offers other diagnostic testing not covered under Vermont’s standards but still quite important.

We offer a new cow test and a new goat test that can be performed with a small sample of milk sent through the mail. This $60 test can help you to avoid unbred cows, subclinical mastitis, staph infections, Johne’s and Leukosis diseases, coliforms, E. Coli and bad milk quality (low fat content).

One visit from the vet is more expensive and time-consuming than this test. Also, studies show that 89 percent of U.S. farms have at least one cow with Leukosis, and 40 percent of the American dairy herd is infected.

Creating a clean space to milk and udder care

There are many ways to lay out a milk parlor, and each has pros and cons depending on the number of cows and style of milking (by hand or by machine). I milk two cows by hand in a 12-foot-by-12-foot stall. Steve Judge, founder of the lab, milks up to four cows in tiestalls with a machine and pipeline. However you lay out your milk parlor, make sure you have a method of keeping things clean.

It may be a bit of challenge and perhaps an issue of cost or spacing, but it’s best to keep all other animals out of the milking parlor. Chickens often carry campylobacter, a very common bacteria that causes gastrointestinal issues. Many illnesses associated with raw and pasteurized milk are from campylobacter and can be as mild as one case of diarrhea. But some can be life-threatening.

After bringing my girls into their clean milk parlor and chaining them to a post, I inspect their udders. If they are dirty, I either brush them off or get a bucket of warm, soapy water and wash them properly. I then dry them with a clean towel. Check the teat ends to make sure there isn’t a little dab of manure stuck in there. Once clean, pre-dip.

An 80 percent reduction in total bacteria count can be obtained with an antibacterial pre-dip versus no pre-milking treatment. I use IO Dip but there are other non-iodine-based dips too. Also, get a dip cup to apply the dip. After dipping, wipe the teats dry with a clean rag. Only use the rag once per quarter per cow to avoid cross-contamination. You can use just one part of the rag for each quarter to save laundry.

After pre-dip, milk out the first 12 or so squirts into a strip cup from each quarter. The first few squirts of milk are the most heavily laden with bacteria and should be discarded. If there is blood or significant chunks in the stripped milk, you’ll know something is wrong and you should set today’s milking aside. Might be time for another round of tests.

Once stripped, move in with your milk pail or connect your bucket milker and milk her all the way out. For hand milkers, it’s important to massage each quarter and milk every last squirt. This will help avoid mastitis, gain a creamier product and give you a heads-up if you find any hard or sensitive spots.

Hand milkers also have the added challenge of protecting the pail of milk from dust and dirt; you can achieve this with a stainless screen. Additionally, if your cow steps in the pail, the milk will have to get fed to pigs or chickens.

Machine milkers will find that, if their equipment is kept very clean, they will have very clean milk since it doesn’t come into contact with the open barn air or other potential contaminants. Furthermore, machine milking will only take five to seven minutes compared to the 30-45 minutes for hand milkers. After you finish milking, dip each teat once more and let that dry on the teat.

Four tips for ensuring clean and safe milk

1.Filter with the quickness

After milking, I release my cows from the parlor and take the milk to my milk room. This room is a lot like a kitchen, kept clean and free of any animals. In here I filter my milk with a stainless milk strainer into a separate stainless milk can (for making yogurt or cheese) or directly into half-gallon jars (for sippin’ milk).

It’s important to filter relatively quickly after milking to get any hair, dirt or manure out of the milk before it can cause widespread contamination. It will also improve the flavor and keeping quality of your milk to filter quickly.

Longer filter time will directly correlate to total bacteria count. Machine milkers get the convenient benefit of an in-line filter either in the bucket or in a pipeline. This is an excellent way to filter very fast and without much trouble.

2.Chill out: Cool milkdown to 40ºF

Best least-cost practice for hand milkers is to place cans or jars of milk into an ice-water slurry to cool down to 40ºF in under two hours. Simply placing warm jars into a refrigerator will not cool milk fast enough. E. coli proliferates in pasteurized and raw milk that reaches temperatures above 40ºF during transportation and handling. Try not to submerge the jar as water can get into the lid before it seals.

The best high-tech option is to use a bulk tank to maintain low temperatures. Bulk tanks agitate the milk, which cools milk very fast, mixes the fat and skim layers that prevents bacterial growth and ultimately extends shelf-life and lowers bacteria counts. Shelf-life can be extended by 100 percent with a bulk tank.

3.Time to clean up

Washing the equipment used to handle milk is the most important step to keep the milk clean. In your milk room you will want to have a big sink to clean all those large stainless cans and containers. First, perform a cold or lukewarm water rinse on milking equipment.

Using hot water right away will burn milk onto your equipment and become a source of contamination. After rinsing, soap it all up and rinse again with as hot a water as you can handle. Biodegradable dish soap is sufficient for cleaning jars and pails.

Cleaning up takes a little longer for machine milkers, who will need to run their machines with cleaning solution for 10 minutes and once per week break down their claw and bucket and clean completely for 30 to 45 minutes.

Once all the equipment is clean, place everything on a clean, dust-free rack to dry. Leave jars and cans open and upside down. Next time you milk, everything should be dry and have no smell to it at all.

You’ll notice if a customer returns a clean jar with the lid tightly screwed on that the inside of the jar smells foul. A jar like that will have to be rewashed. I always leave lids off; air flow and sunshine are the best disinfectants out there.

4.Consider testing your milkat a local dairy laboratory

After you are up and running with your milk routine, consider sending samples out for testing on a regular basis as a way to double-check your milk. Cheese makers send samples every week to make sure of the quality of their inputs as they make cheese.

Vermont Tier II producers are required to test twice per month. I test a couple weeks after my cows freshen in the spring, again if I suspect any mastitis or change my routine during the season, and once more to check if they’re bred in the late summer or fall.

It’s a good idea to test for Johne’s disease and Leukosis once per year, which can be done while checking for pregnancy with the lab’s annual wellness test.

To recap, I recommend testing an animal’s health before joining the herd, creating a clean milking parlor and being diligent in the filtering, cooling and cleaning of your milking equipment.

Following these steps will help you not fear the pathogens and bacteria but make cheese or yogurt with confidence and relish in the metamorphosis of sunlight and grass into a glass of clean, delicious raw milk. PD

This content was originally published at Mother Earth News, a website and magazine about sustainable, self-reliant living. Learn more about Bob-White Systems lab at the website and more about Zigelbaum’s farm at his website.

Photo by Thinkstock.

Nick zigelbaum

Nick Zigelbaum
Lab Director
Bob-White Systems Lab