Skip to comments.Rapid, low-temperature process adds weeks to milk's shelf life
Posted on 07/25/2016 3:41:29 AM PDT by 2ndDivisionVet
WEST LAFAYETTE, Ind. - A rapid heating and cooling of milk significantly reduces the amount of harmful bacteria present, extending by several weeks the shelf life of one of the most common refrigerator staples in the world, according to a Purdue University study.
Bruce Applegate, Purdue associate professor in the Department of Food Science, and collaborators from Purdue and the University of Tennessee published their findings in the journal SpringerPlus, where they show that increasing the temperature of milk by 10 degrees for less than a second eliminates more than 99 percent of the bacteria left behind after pasteurization.
Its an add-on to pasteurization, but it can add shelf life of up to five, six or seven weeks to cold milk, Applegate said.
Pasteurization, which removes significant amounts of harmful pathogens that can cause illness and eventually spoil dairy products, is considered a high-temperature, short-time method. Developed by Louis Pasteur in the 19th century, the treatment gives milk a shelf life of about 2-3 weeks.
The low-temperature, short-time (LTST) method in the Purdue study sprayed tiny droplets of pasteurized milk, which was inoculated with Lactobacillus and Pseudomonas bacteria, through a heated, pressurized chamber, rapidly raising and lowering their temperatures about 10 degrees Celsius but still below the 70-degree Celsius threshold needed for pasteurization. The treatment lowered bacterial levels below detection limits, and extended shelf life to up to 63 days.
With the treatment, youre taking out almost everything, Applegate said. Whatever does survive is at such a low level that it takes much longer for it to multiply to a point at which it damages the quality of the milk.
The LTST chamber technology was developed by Millisecond Technologies, a New-York-based company.
Sensory tests compared pasteurized milk with milk that had been pasteurized and run through MSTs process. Panelists did not detect differences in color, aroma, taste or aftertaste between the products.
Phillip Myer, an assistant professor of animal science at the University of Tennessee and a co-author of the paper, said the process uses the heat already necessary for pasteurization to rapidly heat milk droplets.
The process significantly reduces the amount of bacteria present, and it doesnt add any extra energy to the system, Myer said.
Myer said the promise of the technology is that it could reduce waste and allow milk to reach distant locations where transport times using only pasteurization would mean that milk would have a short shelf life upon arrival.
Applegate said the process could be tested without pasteurization to determine if it could stand alone as a treatment for eliminating harmful bacteria from milk.
The study was funded by the Agricultural Research Service of the U.S. Department of Agriculture, the Center for Food Safety Engineering at Purdue University and Millisecond Technologies.
Interesting. I have questions about the technical process and its scalability.
Sounds good but why have better answers like irradiation not caught on, heating always destroys nutrients...
Hope it hits the market soon. I hate when my gallon of milk goes bad so soon after purchasing it. Of course, the milk industry might not like this process as they wouldn’t sell as many gallons of milk due to spoilage and customers having to go buy another gallon sooner than they would want. Good for the customer, not so good for the quantities of milk producers would be selling.
Good, but how much milk can you carry and store in the fridge?
Latin American nations have been selling warm milk, in a bag that has a shelf life of 90 days for time time now. Big secret is that it tastes batter than the finest milk you can buy from a store here.
What a lot of people don’t understand is when you open a package of food the shelf life is no longer what is printed on it.
Yep, same in Europe and everywhere but here. The “organic” milk sold here refrigerated in cartons (not Tetra packs) is also UHT treated, explaining the much longer shelf life and superior flavor.
“significantly reduces the amount of harmful bacteria present”
And significantly reduces the amount of “good” bacteria present.
I know. Turn into cheese and then add water later....
Why buy the milk when you can feed the cow for free ? Or something like that.
I only buy a half gallon as there are only 2 of us, and I don’t drink it, it doesn’t like me. Skim milk is more like colored water, but it is what hubby is forced to use on his cereal, high cholesterol issue forces a lower fat diet.
Skim doesn’t seem to last as long as whole milk either. Doesn’t cook the same either.
You drink milk for the bacteria? Pasteurization does not reduce the nutritional value of milk.
I’m lucky now to get two weeks out of a gallon of milk before it goes sour.
Radiation scares people.
But, I can say that irradiated milk does not taste the same as fresh milk. I’m not saying that it’s bad, I actually acquired a taste for it, but if you drank a glass of irradiated milk expecting a glass of fresh, you would be surprised.
Get a new doc. Lose the low fat food and switch to low carb food. The cholesterol issue will disappear, and the higher fat food tastes much better.
To clear up a few things.
1) Pasteurization does not sterilize milk. Sterilized milk tastes awful. Pasteurization just reduces the number of bacteria in milk so that it lasts longer. It reduces the number of pathogenic, disease causing, bacteria to below the threshold they need to cause infection in those that drink the milk.
2) Ultra High Temperature (UHT and related acronyms) processing of milk “flash” raises its temperature high enough to kill bacteria, but then it is immediately cooled, limiting the chemical changes that makes sterile milk taste bad. It can typically last in a sealed container, unrefrigerated, for about six months. Most whipping cream is processed this way.
3) Irradiated milk tastes bad, so much so that nobody has applied for government permission to commercially make it.
4) Ordinary Pasteurized cream is acceptable for making home fermented milk products like Creme Fraiche, Crema Mexicana, and Sour Cream. UHT cream does not work as well.
5) The paradox of raw milk is that a small farm, with good hygiene for its cows and frequent on-site testing, will only very rarely encounter any pathogenic bacteria, and almost always catch it before its milk is sold.
However, large factory farms generally do not have good hygiene for their cows, and are unwilling to use either the money or manpower needed, when Pasteurization is cheaper.
But because raw milk is so delicious, making Pasteurized milk taste like ground chalk in water, the dairy industry lobbies continually to prohibit the sale of raw milk.
Quit drinking out the carton! :)
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