Q: What are the differences between "pasteurized" and "ultra-pasteurized" dairy products?
A: Standard pasteurized milk has been HTST pasteurized — meaning "high temperature, short time" heating. The milk is heated to 161.5 degrees F for just 15 seconds, which destroys 99.9 percent of the bacteria. This is the current standard for fluid milk and cheese milk.
Actually, many or most so-called "raw milk" cheese is made from milk brought to the range of 155 degrees F, which is enough to destroy most pathogens, but not the enzyme phosphatase. This milk, technically not pasteurized, can then be made into fully aged "raw milk" cheese. The beneficial phosphatase enzyme acts as a further safety factor, because it aids in digesting any possible remnant bacteria not otherwise disabled during the aging of the cured raw-milk cheese.
Refrigerated HTST pasteurized milk is stamped with a "sell-by" date — generally 14-21 days — and the milk is fine for a few more days. Once opened, any milk should be used within a week or so. The closer to the sell-by date, the shorter the time before it spoils. Regular pasteurized milk has minimal flavor change or nutrient loss.
Ultra High Temperature Pasteurization (UHT), heats the milk to 280 degrees F for two seconds. It is primarily used because it allows a sharp increase in storage. Other factors affecting storage of UHT milk include choice of packaging materials, whether it is shelf-stable (aseptic boxes, where it can be stored unrefrigerated for very long periods, but where nutrients really begin to drop) or whether it is UHT refrigerated milk. Ultra-pasteurized refrigerated milk (most of the ultra-pasteurized milk PCC carries) can be kept refrigerated up to three times longer than standard pasteurized milk.
Significant vitamin losses begin about 65 days after processing and packaging. Therefore, the "sell-by" dates stamped on the cartons (which are set by the producer) should reflect a considerably shorter time period, say 45 to 55 days, so that if purchased on the last date, yet used within a few days, there should be no vitamins lost. In this context, (appropriate manufacturing, handling, packaging, storing, and use) ultra-high temperature pasteurized milk is considered equivalent to regular pasteurized milk, according to the American Dietetic Association.
Flavor is subjective. I know of no "blindfold" taste tests on consumers. Some cooking authorities say ultra-pasteurized cream does not whip well. My personal experience is that the fresher the cream, the easier the whip, but since I only indulge maybe two or three times a year, what do I know? And if ultra-but-organic-cream is what is on the shelf, I'll take it.
Not according to the American Dietetic Association. In fact, the enzyme phosphatase is destroyed by even the much lower temperature (161.5 degrees F) used in regular pasteurization, and no further enzyme degradation is associated with the higher temperature of UHT pasteurization.
In fact, UHT milk is sometimes suggested as providing a better option for those who suffer from Irritable Bowel Syndrome (IBT), but don't want to eliminate milk, which can be a "trigger" food in IBT. UHT milk may be less likely to cause them difficulty than regular pasteurized milk.
Perhaps the most niggling issue of all to some consumers is the fact that only organic brands have ultra-pasteurized milk in the refrigerated case.
Location, location, location!
The economics of dairy production are very tight, but especially so for organic dairies. Organic producers must have access to organic land and funding sufficient for organic herd acquisition and expensive equipment. Because their operations are usually small, there is no "economy of scale."
They must have a farm plan providing for organic replacement stock. They must provide for herd health and maintenance, with no drugs, following organic standards. They must be able to guarantee continued access to 100 percent organic feed. They must pay organic certification fees.
Most organic milk is necessarily processed in plants that mostly process non-organic milk. They must segregate the organic milk production. Even if there is a pool of organic milk and a processor to handle it, many times it still needs to be transported vast distances and the clock is ticking. Then ultra-pasteurization is helpful to maintain a viable, safe milk.
Where it all comes together or falls apart is, can they get that milk to the consumer? How long will it take to transport it to the plant? Can they share that cost by pooling with other organic dairies "up the road." Distance from urban centers, where demand for refrigerated organic milk is highest, is also a critical factor. Every day spent processing, every day spent transporting to the wholesaler, then to the store, into the case, and finally to the consumer, the clock is ticking for liquid milk's use.
Now, perhaps, we can begin to see the reason that much of the organic liquid milk from Horizon and Organic Valley is ultra-pasteurized. Organic producers were reluctant to use the method, primarily because they anticipated that consumers would be leery of the higher temperature and extended dates. Each of the two companies has some milk regularly pasteurized (coming from closer dairies) and some ultra-pasteurized (because of time and distance, pure and simple).
Before providing the UHT pasteurization method, many retailers, including PCC stores, had scores of very dissatisfied customers, returning organic milk because it "turned" so quickly and was unacceptable. Now consumers do have a choice. Choice is good!