2025 May Board Book

Reprinted from California Bountiful ® magazine californiabountiful.com

From cow to carton

Careful processing ensures California milk’s safety and quality

Story by Ching Lee

After milk is standardized into the different fat percentage levels, it goes through pasteurization. This step involves heating milk to a specified temperature and time to kill potential harmful pathogens that could be in the raw milk. Pasteurization techniques can vary depending on what the milk is used for, but Yee says processors most commonly use high-temperature, short-time pasteurization, or HTST, which heats milk to 161 degrees Fahrenheit for 15 seconds. Extended shelf-life milk uses ultra-high temperature, or UHT, pasteurization, heating the milk up to roughly 283 degrees Fahrenheit for two to three seconds. Milk transformed Next, the milk is homogenized, which entails forcing it through small openings under high pressure to break up the fat particles. This step prevents the fat from naturally separating and rising to the top and creates a smooth, uniform texture. Though fluid milk is virtually never exported due to its weight, the nonfat milk solids are. Once separated and dried, the solids become a nutrient-dense, more shelf-stable powder that’s easier to transport. The powder can be reconstituted, used in recipes and is a key ingredient in baby

Because milk comes out of a cow resembling the finished product, it would be easy to assume that processors simply bottle it, ship it to the store and call it a day. But the highly regulated process involves several steps to ensure the product meets federal and state food safety, nutritional and quality standards. When cows are milked, the raw milk is first stored in a refrigerated holding tank at the farm. Milk trucks visit a dairy daily to collect that milk and ship it to the processing facility. Before it can be delivered to the processor, a sample is taken from the tank to test for impurities. The milk is tested again once it arrives at the plant, this time for the milk components that determine how much farmers are paid, says Ben Yee, director of processor partnerships for the California Milk Advisory Board. Milk is about 87% water and 13% solids, which consist of fat, protein, sugar (or lactose) and minerals such as calcium and phosphorus. But milk composition can vary based on a cow’s diet, the environment and other factors. “You could have cows that are more stressed because of the extreme temperature changes,” Yee says. “They go through body reactions to the environment. It’s no different than human beings.”

formula. Mexico remains the top export market for U.S. milk powder, according to the U.S. Dairy Export Council. The water that’s left over from drying milk is recycled, such as for cleaning, irrigating or other uses, Yee says. “It doesn’t just go into a drain and out to the sewer,” he adds. The milkfat that’s not put back into milk is churned into butter. Conventional butter is typically 80% milkfat, while European-style butter contains 82% or higher milkfat. Buttermilk is the fermented liquid left over after making butter. In addition to butter, other common uses for milkfat include cheese, ice cream, sour cream, heavy cream, whipping cream and half-and-half. Federal standards call for a certain amount of milkfat in dairy products. For example, cottage cheese contains at least 4% milkfat, half and-half has 10.5% to 18%, and heavy cream consists of at least 36%. “It is fascinating all of the different products that are made from the milk itself and all of the different processes that everything goes through,” Yee says.

Exceeding federal standards To ensure a consistent product, processors separate the water and milk components and then recombine them, adding the right amount of fat and milk solids back in to make whole milk, 2% reduced fat, 1% low fat and skim milk. Though it’s known as nonfat or fat-free milk, skim milk contains a tiny amount of milkfat—no more than 0.2%—and at least 9% milk solids under California standards, according to the California Department of Food and Agriculture. That means even though there is virtually no fat in skim milk, it is not simply watered-down milk thanks to the nutritional values in the milk solids. Similarly, reduced-fat milk contains 10% solids, low-fat milk has 11%, and whole milk consists of 8.7% solids and at least 3.5% milkfat. Yee points out that the state’s standards, which date back to the early 1900s and have evolved over time, call for slightly higher minimum levels of milkfat and milk solids compared to federal standards. “To put it in a simple way, California standards ensure higher protein content, higher nutritional quality to meet consumer needs,” he says.

Ching Lee clee@californiabountiful.com

MILK PROCESSING

MILK

DAIRY FARM

TRANSPORT

MILK & DAIRY PRODUCTS

PROCCESSING

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Spring 2025