New study validates light blocking efforts: teens taste light-oxidation in milk and don't like it

Dairy Foods,  Sept, 2002  by Kathryn Chapman

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Smith Dairy Products, Orrville, Ohio, has used the yellow pigmented, Super Jug[TM] for two years, with gradual success. Initially, consumers resisted the new package according to Stephen Schmid, president. They wanted to see the milk, and the yellow colored jug had some consumers confusing it with orange juice. Now sales are building. "We have won them back by promoting the benefits of the package," Schmid says. "One consumer I spoke with said, 'I hate the yellow jug, but love the product that comes from it."'

Retailers love the product because it sells for an extra 25 cents a gal.

Cheryl Bell, public relations manager, for Schroeder Milk Co. Inc, Maplewood, Minn., says Schroeder has used the white pigmented bottles across its entire line of fluid milk for several months.

Labels, such as full-body stretch sleeves or shrink sleeves, are not only attractive, but help block light. Dean Foods' Milk Chug[TM] and the Land O Lakes Grip-N-Go[TM] single serve HDPE containers both use shrink sleeves. Smith is one of a number of processors who also use shrink sleeves on bottles.

Even a brief, moderate light exposure of 2 hours at 2000 lux can reduce the nutritional value and can produce detectable off- flavor of milk. Approximately half of the plastic containers in a given dairy case remain under lights for at least eight hours. Thus, the majority of milk in light-transmissible containers could have detectable light-oxidized flavor defects. There are many ways to block light. Processors have found that despite the increased packaging cost, sales and profits have increased due to the protection of milk's flavor and nutrients. For milk to be competitive in the beverage market, it must be protected from light exposure.

Time Parameters for Light Damage to Milk

Time of   % of Panelists Who
Exposure  Detect of Flavors

1/2 Hour        34.5%
1 Hour          45.6%
2 Hours         50.0%
3 Hours         70.7%

* According to a study done by Cornell University's Milk Quality
Improvement Program (MQIP), when milk was exposed to light for as little
as a 1/2 hour, 34.5% of teen panelists could detect an off-flavor.

Note: Table made from bar graph

Kathryn W. Chapman is a researcher at Cornell University - Ithaca, N.Y.

Sensory Threshold of Light-Oxidized Flavor Defects in Milk by Kathryn Chapman, Lynn Whited and Kathryn Boor, Journal of Food Science (in press)

Vitamin A Degradation and Light-Oxidized Flavor Defects in Milk by Lynn Whited, Barb Hammond, Kathryn Chapman and Kathryn Boor was published in vol. 85, No. 2, 2002 of the Journal of Dairy Science.

For more information about the study contact Cornell University: 607/255-7643.

COPYRIGHT 2002 BNP Media
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