It comes in a thick cardboard box and can be kept without
refrigeration for six to nine months if unopened. Is it really milk?
UHT milk has been available in Malaysia since the 1970s. When it
entered the market, it had to jostle with milk powders, condensed
milk, evaporated milk and pasteurised milk for a slice of the big milk
pie.
Now, 40 years on, UHT milk has not only managed to become a mainstay
on supermarket shelves, its consumption has in fact been increasing
year on year, reports Dutch Lady Milk Industries Berhad, Malaysia’s
leading milk brand and the first company in the country to market milk
in UHT packaging.
Michael Ockerse of Pureharvest says UHT results in a greater
reduction in bacteria and heat-resistant enzymes. “We attribute this
to the increase in awareness of the benefits of milk, coupled with
trends that indicate that a bigger portion of consumers rely on the
convenience that UHT packaging offers,” says Aznil Sharizat Mahidin,
head of the corporate communications department in Dutch Lady.
“Also, as the socio-economic status of consumers improves, UHT milk is
often the preferred choice over family powdered milk,” she adds.
Still, market research indicates that the most popular type of milk
consumed in Malaysia is sweetened condensed milk – that’s what goes
into our teh tarik.
But what exactly is UHT milk? And how can it last so long without refrigeration?
UHT stands for Ultra Heat Treated or Ultra High Temperature processing
– a method of sterilising food by heating it to temperatures upwards
of 130°C for a few seconds, and then rapidly cooling it. The procedure
is used for sterilising fruit juices, soymilk, soups, ketchup, salad
dressings, and particularly, milk.
“Pasteurisation is the minimum amount of processing for milk as
required by Australian law and is specified as 72°C for 15 seconds,”
explains Michael Ockerse of Pureharvest, one of Australia’s largest
organic milk producers. At Pureharvest, UHT milk is processed at 132°C
for two to three seconds.
“The increased temperature at which (UHT) milk is treated results in a
greater reduction in bacteria and heat-resistant enzymes in comparison
to milk that undergoes pasteurisation, giving it an extended shelf
life,” explains Amar Srivastava of Australia’s largest milk processor
Murray Goulburn, whose company produces Australia’s top UHT milk
brand, Devondale, brought in by Pok Brothers Sdn Bhd.
Pasteurised milk and UHT milk are both packed aseptically after the
heat treatment, the former in milk cartons, and the latter in Tetra
Paks.
“Tetra Pak has seven layers to maintain the quality of milk and reduce
bacterial contamination,” explains Srivastava.
The Swedish patented packaging box is made from layers of polyethylene
plastic to keep it airtight, foil-laminated to keep out light and
thick cardboard layers to provide structural integrity.
The reinforced packaging and the high-heat treatment is the reason UHT
milk can sit happily at room temperature until opened (after which it
should be treated like any fresh milk: refrigerate and use within a
few days), while pasteurised milk must be refrigerated from factory,
all through the distribution system to the stores, and finally to your
home.
Safe to glug: UHT milk is packed aseptically into the sevenlayered
Swedishpatented Tetra Pak to maintain its long shelf life.
“UHT milk has a nine-month, best-before date, but it is still safe for
consumption up till 12 months,” says Ockerse. “Pasteurised milk has a
shelf life of only 14 days.”
“There are no preservatives in UHT milk. The long shelf life is
guaranteed through high temperature processing and aseptic filling
containers,” Sharizat reiterates.
In many parts of the world, UHT milk is still regarded as suspect, if
not for the presumed presence of preservatives, then for the effects
of the high-heat processing.
“UHT processing does not change the molecular structure of milk,”
explains Sharizat. “However, it does change the configuration of the
proteins. This process is called denaturation, and is also the reason
eggs become hard when boiled and meat becomes firm when cooked.”
UHT milk produced in the early years of the technology’s development
was characterised by a strong burnt taste, an effect of Maillard
browning caused by the high-heat treatment. But UHT milk production
has experienced quantum leaps of improvement since then.
Automated machines do the packing work.
Studies have discovered that by altering the processing parameters of
UHT milk, such as using indirect steam injection rather than direct
heat application, and increasing the speed at which the milk is cooled
after heating, the resulting milk tastes sweeter, and the burnt taste
is significantly reduced to the point where it is not discernible to
most consumers.
The addition of epicatechin, an antioxidant-rich flavonoid compound
abundant in tea and chocolate, has also been found to reduce the
“cooked” aroma of UHT milk. But for those wary of additives, a quick
check of the label should reveal if there are additives in your milk,
and the nutritional content is shown on the pack, too.
“UHT milk has the same nutritional goodness as pasteurised milk, and a
similar taste profile,” says Srivastava. “Like fresh milk, UHT milk is
a rich source of over 10 essential nutrients, including calcium,
phosphorus, potassium, riboflavin, potassium, vitamins A and B12,
magnesium, carbohydrate, protein and zinc.”
“UHT processing does not change the nutritional content of milk,”
concurs Sharizat, “but it can affect digestive properties, which is
mainly of importance to newborns,” and by extension, expecting
mothers.
“The only nutrients affected by heat treatment are some of the
vitamins, especially vitamin C. This is, however, not present in
significant amounts in milk,” says Sharizat. Hence, we don’t usually
rely on milk for our intake of vitamin C. “Losses for other vitamins
are minimal,” she adds.
“Based on the Malaysian Adult Nutrition Survey published in 2008, we
know that protein and vitamin A intake in Malaysia is at the
recommended level, but calcium intake is on average only at about 50%
of the recommended value. This is a clear indication that Malaysian
adults are not consuming sufficient amounts of dairy products,”
observes Sharizat.
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Green milk – food for thought
The evolution of milk
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