Milk is picked up from a dairy farm every day. Some farms like New Generation Dairy load their cooled milk directly into an insulated semi tanker so it is ready to go. Other dairies store their milk in refrigerated bulk tanks. A truck comes to these farms every day, pumps the milk from the bulk tank into the semi tanker, and hauls the milk to the processor. If a dairy doesn’t have enough milk to fill a tanker, the driver will stop at a few dairies to get a full tanker before heading to the processor. The driver will take samples of milk from each farm before filling the tanker.
At the processor, samples are taken from each and every tanker of milk. The milk is tested for a list of antibiotics and other medications. There is a zero-tolerance policy for medications in milk. If any medication is found in a tanker of milk, the entire tanker is disposed of, at the farmer’s expense! If a tanker has milk from more than one farm, the individual samples are tested so the problem can be traced back to the right farm.
The milk samples are also tested for somatic cell count (SCC). All milk has some cells in it. The healthier and less stressed the cows are and the cleaner their living environment is, the lower the SCC will be. Typically, a lower SCC is associated with better quality milk. So farmers get a monetary bonus when the milk from their dairy meets certain guidelines for low SCC.
Milk samples are tested for the amount and types of bacteria in them. All milk (all food, really) has some bacteria in it. This is why pasteurization of milk is so important. If the samples have too many bacteria, they are discarded. If the samples have very low numbers of bacteria, the farmers are rewarded for good quality milk. Like with the SCC, lower bacterial numbers are related to better overall health and well-being of the cows.
Milk samples are also tested for protein and butterfat content. Higher protein and higher butterfat are also associated with higher quality milk. This is associated with the cows’ diets. The better quality feed they are given, the better quality milk they can make! Again, farmers are rewarded for higher quality milk.
All this happens before the milk is pasteurized and homogenized and prepared for shipping to the grocery stores. And even though milk has to go through all these steps – and pass all these tests! – before it gets to you, milk gets from the cow to the grocery store in only two days!