UPDATED: July 6, 2012
The recent trade dispute between Pine Hill Dairy and the government of Trinidad and Tobago is about package labeling – according to the news media.
With the ongoing dispute as a background we thought we’d revisit this article by Dr. Lucas that explains why you still can’t stand the taste of the new stuff, er, milk…
The following article was submitted to BFP by Dr. Robert D. Lucas.
Pine Hill Dairy’s “new” milk
Recently, in the local press, concerns have been raised about the labeling as “Fresh” and the refrigerated storage of ultra-pasteurized milk (UP). Pine Hill Dairy (PHD), in an attempt to address these concerns, placed full-page advertisements in the press. I will now explain the concepts of pasteurization, sterilization and fresh as applied to food products. A critical examination of the PHD advertisement is also given.
Pasteurization is the process whereby a food product is heat-treated, destroying all pathogenic or disease causing organisms present in the food. Pasteurization does not result in the destruction of all of the micro-flora ( organisms). present. Some of the organisms which survive pasteurization can cause spoilage. Therefore, all pasteurized foods must be held refrigerated (pasteurized canned hams, pasteurized milk etc.).
Sterilization is the process in which all pathogenic and non-pathogenic spoilage organisms, including most spores are destroyed. No attempt is made to destroy all of the micro-flora present, since such an action results in the destruction of nutrients as well as the texture of the food. In food, this process is called commercial sterilization. Ultra high temperature (UHT) treated milk is a commercially sterile product.
According to the Code of the Federal Register (CFR) § 101.95 sub part F: Food Labeling. “The term fresh is used to describe pasteurized whole milk……; because the term does not imply that the food is unprocessed (consumers commonly understand that milk is nearly always pasteurized”). Title 21. Food and Drug Administration (FDA) 2010. Department of Health and Human Services, USA.
When milk is heat-treated, sugars in the milk, in the presence of amino acids undergo the Maillard reaction (non-enzymatic browning). This results in a burnt or cooked flavor and the development of off colors. The longer the exposure to heat and the higher the temperature, the greater is the adverse effect. For this reason, all pasteurized foods are rapidly cooled down. UHT milk is no exception to this rule. According to (Anon). 2007. “Dairy Foods Science Notes” Cornell University: “Ultra-pasteurized milks will often have more of a “cooked” flavor when compared to conventionally pasteurized milk.”
It should be noted here that, neither pasteurization nor sterilization destroys native alkaline proteinases as well as bacterial proteinases found in milk. Also, when heated, lipolysis(break down of fats into free fatty acids) occurs.
“All of these processes affect the flavor of milk.”
An examination of the graph given by PHD as well as the use of the term spiked, tend to indicate that the time taken to raise the temperature of UP milk from 80°C to138°C was instantaneous. PHD failed to point out that there are direct and indirect methods of heat treating UHT milk. When direct heating is done,the heat process for UHT milk takes 45 seconds.Goff (2010) “UHT Processing.” University of Guelph). In food processing, the time taken to raise the temperature of a food from temperature x to temperature y, is called the “coming up time.” It is noticeable, that PHD does not indicate how long the coming up time was.
One is left to wonder why would PHD stop producing a product, with a shelf-life of six-twelve months at ambient (room) temperature, to which the consumers’ taste buds were accustomed, in preference for one with a shelf-life of three months and which must also be refrigerated.
Energy costs in Barbados are very high. UHT procedures require complex equipment and a high level of technical know-how. “Complexity of equipment and plant are needed to maintain sterile atmosphere between processing and packaging (packaging materials, pipe work, tanks, pumps); higher skilled operators; sterility must be maintained through aseptic packaging.” Goff. (2010). Aseptic packaging of UHT milk differentiates if from UP milk. As a result, the latter must be refrigerated. It should be noted here that UHT milk has been produced in Trinidad since the 1970’s. Indeed, In 1973 I visited Nestle as a food science student to observe the process.
In food, the processor never has preconceived notions of the food preference of the consumer. This is what I find most amusing about the advertisement.
When the Coca-Cola corporation introduced new coke and tried to force it down the throats of the American consumers, the latter refused to purchase it. Coke had to revert to its original formula. It is only when a company is a monopoly that, it can ride rough shod over the views of the consumer. The PHD advertisement alluded to tests being done locally. There was some mention elsewhere about overseas testings. No where was it mentioned if the tests were done by trained panels of local testers. Was the testing done in house or out sourced? Were statistical analyses of the data done? Was a consumer preference taste-test done, employing 1000 or so persons? The latter test gives a true indication of the likes and dislikes of the consuming population. Testing overseas is a waste of time, because taste varies from place to place.
Finally, the advertisement extols the fact that the pack for UP milk consists of six-layers. According to the Alaska Commission on Aging. (2006). “Senior meal planning guide.”UHT milk is packed in a five layer sterile laminated “box.” In both instances, the packs for UHT and UP are non-environmental friendly.
Robert D. Lucas, PH.D.