Refrigerated Milk Displays in Supermarket Dairy Cabinets

Refrigerated milk in supermarket cabinets can develop off-flavors and lose nutrients after four minutes of exposure to direct sunlight, and after four hours of exposure to fluorescent display case lighting.

Milk in glass or plastic containers are most vulnerable, but off-flavors will also develop when milk is packaged in paper cartons.

Promolux Safe Spectrum fluorescent lamps add LEDs emit lower levels of UV and visible spectrum radiation, thus reducing the rate of damaging chemical reactions in milk and dairy products.

Lipid Oxidation of Milk in Grocery Store Milk Displays



When milk is exposed to sunlight or to the fluorescent lighting commonly found in refrigerated dairy display cases, the light initiates two chemical reactions which result in off-flavors and the loss of nutrients.

First, whey proteins, composed of amino acids containing sulfur, degrade and break down, producing “sunlight” flavors reminiscent of burnt feathers or burnt hair that can last for two to three days.

In the second reaction, the unsaturated fatty acids in milk lipids (milkfat triglycerides / triacylglycerols) become oxidized, producing malodorous carbonyl compounds that taste metallic or cardboardy and do not dissipate.

Various studies have found that these chemical reactions can occur in milk after four minutes of exposure to direct sunlight, and after four hours of exposure to fluorescent lighting, while the off-flavors were detected by trained tasters after milk was exposed to light for 15 to 30 minutes, and by consumers after milk was exposed to light for one to two hours.

In a Pennsylvania study, light-related off-flavors developed within 36 hours in almost half of 449 samples of milk in translucent plastic jugs. Another study found that off-flavors were present in approximately 80% of the blow-mold plastic milk containers exposed to fluorescent lighting in supermarket dairy display cases.

Milk Nutrient Loss in Retail Milk Showcases

The following nutrients are lost from milk during lipid oxidation: Vitamin A (especially added Vitamin A), Vitamin D (especially added Vitamin D), riboflavin (Vitamin B2), Pyridoxine, Vitamin B12, and Vitamin C (ascorbic acid, present in small quantities in milk). Riboflavin is destroyed by ultraviolet light.

One study found that 90% of the added Vitamin A and 8% of the riboflavin was lost from milk in polyethylene containers after 24 hours of exposure to fluorescent lights, with increased loss of these nutrients as the fat content of the milk decreased.

Flavor Changes of Milk in Commercial Milk Merchandisers

When milk is exposed to light, two chemical reactions occur that cause the milk to taste like burnt feathers, burnt hair, cardboard, or metal.

Factors that affect the rate of flavor change and nutrient loss in milk caused by exposure to display case lighting are the intensity of the light, the wavelengths present in the light, the distance between the fluorescent light bulb and the milk, the material of the container, the amount of surface area exposed to the light, the temperature of the milk, and the duration of light exposure. The higher the fat content, the more vulnerable the milk or cream is to the off-flavor effects of lipid oxidation.

Milk in light-transmissible containers such as transparent glass or plastic is most commonly affected but milk in paper cartons can also be affected when the cartons are exposed to intense light for long periods of time.

Promolux Lamps – Merchandise Milk Products For Freshness and Nutrition

Promolux balanced spectrum low radiation lamps and LEDs are ideal for milk and dairy product displays. Compared to other fluorescent lighting, Promolux lamps prevent 86% of UV B radiation and 52% of UV A radiation from penetrating a products packaging ensuring it lasts longer as well as the nutrients inside.

With Promolux lamps and LEDs installed in your dairy cases, you can be confident knowing that as shoppers pass by the vivid colors of the packaging will stand out and draw their attention to the case which holds a variety of nutritional and flavorful dairy beverages and products for the whole family.

Fit your dairy showcases with Promolux and see what the fuss is all about! Request a quote online right now and we’ll email you a custom quote just for your business.