"High heat during the UHT process can cause Maillard browning and change the taste and smell of dairy products."Ultra-high temperature processing, (less often) ultra-heat treatment (both abbreviated UHT), or ultra-pasteurization is the sterilization of food by heating it for an extremely short period, around 1–2 seconds, at a temperature exceeding 135°C (275°F), which is the temperature required to kill spores in milk. The most common UHT product is milk, but the process is also used for fruit juices, cream, soy milk, yogurt, wine, soups, honey, and stews. UHT milk was invented in the 1960s, and became generally available for consumption in the 1970s.
UHT milk has a typical shelf life of six to nine months, until opened. It can be contrasted with HTST pasteurization (high temperature/short time), in which the milk is heated to 72°C (161.6°F) for at least 15 seconds.
- UHT and pasteurized milk contains the same amount of calcium.
- Some nutritional loss can occur in UHT milk.
PopularityUHT milk has seen large success in much of Europe, where across the continent as a whole 7 out of 10 Europeans drink it regularly. In fact, in a hot country such as Spain, UHT is preferred due to high costs of refrigerated transportation and "inefficient cool cabinets". Europe's largest manufacturer, Parmalat, had $6 billion of sales in 1999. UHT is less popular in Northern Europe and Scandinavia, particularly in Denmark, Finland, Norway, Sweden, the United Kingdom and Ireland. It is also less popular in Greece, where fresh pasteurized milk is the most popular type of milk.
In June 1993, Parmalat introduced its UHT milk to the United States. However in the North American market, consumers have been uneasy about consuming milk which is not delivered under refrigeration, and have been much more reluctant to buy it. To combat this, Parmalat is developing UHT milk in old-fashioned containers. Many milk products in North American foods are made using UHT milk, such as McDonalds McFlurries. UHT milk is also used on airplanes.
UHT milk is sold on American military bases in Puerto Rico. and Korea[who?] due to limited availability of milk supplies and refrigeration.
UHT milk gained popularity in Puerto Rico as an alternative to pasteurized milk due to environmental factors. For example, power outages after a hurricane can last up to 2 weeks, during which time regular pasteurized milk would spoil from lack of refrigeration.
EnvironmentIn 2008, the UK government proposed a 90% UHT milk production target by 2020 which they believed would significantly cut the need for refrigeration, and thus benefit the environment by reducing green house emissions. However the milk industry opposed this, and the proposition was quickly abandoned.
- "UHT Processing". University of Guelph, Department of Dairy Science and Technology. Retrieved 2008-01-07.
- Elliott, Valerie (2007-10-15). "Taste for a cool pinta is a British Tradition". London: The Times. Retrieved 2008-04-03.
- Clare, D.A.; W.S. Bang, G. Cartwright, M.A. Drake, P. Coronel and J. Simunovic (1 December 2005). "Comparison of Sensory, Microbiological, and Biochemical Parameters of Microwave Versus Indirect UHT Fluid Skim Milk During Storage". Journal of Dairy Science 88 (12): 4172–4182. doi:10.3168/jds.S0022-0302(05)73103-9. PMID 16291608.
- "Taste for a cool pinta is a British tradition". The Times. Retrieved 2008-04-03.
- Greg Morago (27 December 2003). "UHT: Milking it for all it's worth". Hartford Courant. Retrieved 2008-04-03.
- Solomon. Zaichkowsky, Polegato.Consumer Behavior: Pearson, Toronto. 2005. pg 39
- "Without prejudice.". Dairy Industries International.. Retrieved 2008-04-03.
- Elliott, Valerie (2007-10-15). "The UHT route to long-life planet". London: Times Online. Retrieved 2008-03-01.
- "Udio trajnog mlijeka veći od 70%". Ja Trgovac. Retrieved 2010-03-05.
- Janofsky, Michael (1993-06-26). "Seeking to Change U.S. Tastes; Italian Company Sings The Praises of UHT Milk". The New York TImes. Retrieved 2008-04-03.
- "Dairyman wants to send milk to Middle East". Deseret News. Retrieved 2008-04-03.
- "Dairy Road Map outlines target for greenhouse gas cut". Farmers Guardian. Retrieved 2008-04-03.
- Elliott, Valerie (2007-10-15). "The UHT route to long-life planet". London: Times Online. Retrieved 2008-04-03.
- "Tetra Pak to set up recycling facility,". The Nation. Retrieved 2008-04-03.
- An article focusing on the negative aspects of UHT milk from the Weston A. Price Foundation
- Milk in a Box. From: Interesting Thing of the Day
|Written by Linda Joyce Forristal, CTA, MTA|
|Sunday, 23 May 2004 16:41|
In the Kitchen with Mother Linda
Today, an increasing amount of milk found in conventional grocery stores--including most organic milk--is ultra-pasteurized. The official U.S. government definition of an ultra-pasteurized dairy product stipulates "such product shall have been thermally processed at or above 280° F for at least 2 seconds, either before or after packaging, so as to produce a product which has an extended shelf life under refrigerated conditions." Confusingly, ultra-pasteurized milk is oftentimes referred to as or labeled as UHT, for "ultra-high temperature." It is the high-temperature processing that gives the milk an extended shelf life (ESL).
Why do processors embrace UHT milk? Because today’s milk is no longer a local product; it is processed in huge processing plants and then shipped all over the country. When packaged in aseptic containers, UHT milk remains stable at room temperature for up to six months. Its extended shelf life with refrigeration in standard packaging, such as plastic bottles, is up to 50 days--enough time for it to be shipped across country, or internationally, and sold to customers far from the milk’s origin.
HARMFUL PROCESSIn the commercial processing of UHT milk, raw milk is first preheated to 176-194° F, then submitted to one of two heating methods: direct or indirect. In the direct method, milk is injected with superheated steam or the milk is sprayed into steam. This raises the temperature of the milk immediately, but also slightly dilutes it. The extra water is removed when the milk is subsequently cooled in a vacuum chamber. Indirect heating occurs by bringing milk into contact with super-heated metal plates that have been heated by steam--hence, the steam is "indirectly" heating the milk. Some new systems combine the two processes.
According to Lee Dexter, microbiologist and owner of White Egret Farm goat dairy in Austin, Texas, ultra-pasteurization is an extremely harmful process to inflict on the fragile components of milk. Dexter explains that milk proteins are complex, three-dimensional molecules, like tinker toys. They are broken down and digested when special enzymes fit into the parts that stick out. Rapid heat treatments like pasteurization, and especially ultra-pasteurization, actually flatten the molecules so the enzymes cannot do their work. If such proteins pass into the bloodstream (a frequent occurrence in those suffering from "leaky gut," a condition that can be brought on by drinking processed commercial milk), the body perceives them as foreign proteins and mounts an immune response. That means a chronically overstressed immune system and much less energy available for growth and repair.
RESEARCHScientists in Australia, a country with a huge dairy industry, have taken the lead in researching UHT milk. A 2002 paper discusses how UHT processing and subsequent storage causes several changes affecting the shelf life of UHT milk. The changes include: whey protein denaturation, protein-protein interaction, lactose-protein interaction, isomerisation of lactose, Maillard browning which imparts a burnt flavor, sulphydryl compound formation, formation of a range of carbonyl and other flavor-imparting compounds, and formation of insoluble substances. According to the authors Datta and Deeth, these changes "ultimately reduce the quality and limit the shelf life of UHT through development of off flavors, fat separation, age gelation and sedimentation." Nevertheless, according to the report, the milk remains "commercially stable."
A thorough reading of their paper reveals a very interesting point. During the heating process, the aforementioned sulphydryl compounds impart a very strong cabbagy off-flavor to UHT milk that is most noticeable immediately after heating. These compounds dissipate during storage, but approximately one month into storage, UHT milk begins to deteriorate and is described in the industry as "stale." In the later stages of storage, a bitter taste develops and then it undergoes "age gelation," a process in which the milk becomes more viscous and eventually loses fluidity. So, it seems the optimum time to drink UHT milk with any degree of enjoyment, if that’s even possible, is limited to the interval between the dissipation of the cabbage flavor and the onset of staleness, bitterness and gelatinous conditions. In the U.S., these off-flavors seem to go unnoticed, which makes me wonder whether some kind of flavorings or other chemicals are being added to UHT milk? If the whole industry does this, they don’t need to list such additives on the label because it is an "industry standard."
PACKAGINGUHT milk was introduced by the Italian dairy company Parmalat, which sold UHT milk in aseptic tetra-brik containers as a convenience food to Europeans, most of whom lived in apartments and had small refrigerators. That strategy didn’t work in the U.S., where almost everyone has a large refrigerator and where consumers still value "fresh" milk. In the early 1990s, in order to overcome American consumer resistance to milk that didn’t need to be refrigerated, Parmalat implemented an aggressive marketing plan as well as a strategy to overcome "regulatory impediments," hoping to carve out a niche in the U.S. milk market. While little boxes of Parmalat UHT milk can be found in the grocery aisle, most U.S. milk producers package UHT milk in cartons and plastic bottles identical to those containing pasteurized milk.
While UHT milk remains popular in Europe and Brazil, in the United States, consumer resistance has spurred Horizon and Organic Valley, the major producers of organic milk, to reintroduce pasteurized milk in some locations where they have local sourcing and nearby milk plants. In the Washington, DC area, Horizon sells UHT milk in the supermarkets and pasteurized milk in the upscale markets like Whole Foods.
PACKAGINGWhile the processing of UHT milk creates palatability problems and possible health risks, so does its packaging--both the aseptic boxes and plastic containers. For example, phthalates and other endocrine disrupting compounds (EDC) can leach into the milk. In a recent study published in the Journal of Agricultural and Food Chemistry, investigators measured the presence of nonylphenol (NP), bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE) in two brands of UHT milk in tetra-brik containers. These containers are designed to be stacked on pallets and are lined with polyethylene. They also looked at EDCs in two brands of milk that had been bottle sterilized (heated to at least 212o F) "for a length of time sufficient to render it commercially sterile" and in one brand of canned powdered infant formula.
All the samples contained measurable levels of endocrine disrupting substances that leaked from the plastic of the containers, or plastic lining the containers. Even when kept cold, plastic will leach some chemicals into the liquid it contains; filling plastic-lined containers with superheated milk or subjecting liquid-filled containers to high heat is a recipe for the release of phthalates and similar substances. The researchers noted that the levels of these compounds in the samples studied did not achieve "the maximum leached level allowed by law." Their concluding comment, however, is more pessimistic: ". . . the impact these compounds may have on organisms and human beings needs to be further studied, especially with regard to accumulation, degradation and possible effects within the endocrine system."
UHT MILK IN YOUR FUTURE?In the fall of 2004, we learned from a dairy inspector in a mid-Atlantic state that the FDA had conducted a nationwide conference call with the dairy departments of all 50 states. There were two reported topics of discussion on the agenda. The first topic concerned raising the required temperature of pasteurization. The stated reason: many organisms have become heat resistant and now survive the pasteurization process. The Johne’s, or paratuberculosis, bacterium, is a good example. Johne’s disease is endemic in today’s confinement dairies and has been linked to Crohn’s disease in humans. Many samples of pasteurized milk now test positive for Johne’s bacteria. B. cereus and botulism spores also survive, as do those of protozoan parasites.
Is the FDA planning to raise the required temperature of pasteurization to that now used in ultra-pasteurization? If so, the agency has not yet published an official plan. The 2005 "Program Priorities" for the FDA’s Center for Food Safety and Applied Nutrition (CFSAN) include finding ways to reduce the incidence of foodborne Listeria outbreaks, which includes continuing to develop and deliver State and Federal (web based) curricula for "Listeria control implementation for manufacturers and retail/food service operators." Whether this is a covert move that will eventually lead to raising the temperature of pasteurization remains to be seen. Such a move would redefine ultra-pasteurization as pasteurization so that the words "ultra-pasteurization" or UHT might then not have to appear on the label. The industry would certainly be happy about such a move, but would consumers? Any major move in this direction requires the FDA to keep the public informed through an Advance Notice of Proposed Rulemaking (ANPRM), which should include a period for public comment.
The second reported topic of discussion during the FDA dairy meeting was an organization called the Weston A. Price Foundation. We are definitely on their radar screen!
A CULTURE PROBLEMIn the name of science, I decided to do an experiment. I usually make homemade yogurt with a Bulgarian culture and the best quality milk I can find. Raw milk is ideal, but sometimes I have to settle for pasteurized, un-homogenized milk. Both raw and pasteurized, un-homogenized milk produce a firm-textured yogurt with a delectable layer of cream on the top. This time, I bought a quart container of organic Horizon UHT whole milk and cultured it exactly the same way. It took a few hours longer to set up and it never attained the consistency I have come to expect and enjoy. When I tried to spoon some out of the jar, it dissolved into small curds instead of staying in a firm mass on the spoon. It became very watery and unappetizing--and ended up down the sink instead of in my family’s stomach.
At least pasteurized milk will make an acceptable yogurt. Milk that has been sterilized will not. I haven’t noticed the UHT label on any cheese packages either. Since ultra-pasteurized or UHT milk will not adequately support microbial life, it is unlikely that it will adequately support human life either. The fact that the processing and storage of UHT milk is so horrendous makes me wonder why they bother. Fermentation is the best way to extend milk’s shelf life and should be re-examined as a better alternative.
THE ENRON OF EUROPEIn the 1950s, Italian scientists published studies with titles like "Ultra-pasteurization of milk II. Experimental research on the preservability of ultra-pasteurized and pasteurized milk bottled under the same conditions." Such studies undoubtedly provided the ultra-pasteurization know-how to Parmalat Finanziaria, a company started in 1961 by a young Italian entrepreneur named Calisto Tanzi. Today, Dow Jones ranks Parmalat as the world’s number one producer of UHT milk. While Parmalat’s milk may be "stable," its finances are anything but.
In 2004, Parmalat declared bankruptcy both in Italy and the United States after a major financial crisis that involved efforts to hide huge losses and siphon off money to the founding Tanzi family. Thousands of investors were taken to the cleaners with fancy shell games in the Cayman Islands, a situation that gave Parmalat the name of the European Enron. One such scheme was arrogantly, and appropriately, named Buconero, or black hole.
Shortly after the scandal broke, the U.S. Securities and Exchange Commission filed a lawsuit against Parmalat for selling $1 billion of fraudulent bonds to U.S. investors. On January 7, 2005, although $9 billion in debt and with protests from jilted investors, Parmalat managed to wrangle a $15 million debtor-in-possession credit line from the US Bankruptcy court in Manhattan. Parmalat claimed it needed the line of credit to buy enough fresh milk to keep its dairy operation running and make payroll. Why would any responsible bank lend them this money? A wise man once said, "Owe a little to the bank, and they own you; owe a lot, and you own them."