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Refrigerated Cheese Displays in Grocery Store Showcases

Cheese is light sensitive but is often packaged in clear wrapping, which leaves the cheese vulnerable to color fading and discoloration. When exposed to UV radiation, unpackaged feta will develop an off-flavor and may turn yellow.

Promolux lamps minimize the emission of damaging visible spectrum and UV wavelengths and thus reduce shrinkage.

For dairy science references and excerpts click here.

Photodegradation of Mold Retardant in Retail Cheese Displays

Natamycin is an antimicrobial mold inhibitor added to the surfaces of retail cheeses to prolong the shelf life of cheeses, especially those with large surface areas that are most vulnerable to mold growth such as sliced or shredded cheese.

However, natamycin quickly degrades when exposed to the ultraviolet radiation emitted by the supermarket fluorescent lighting commonly used in retail dairy display cases.

Promolux full balanced spectrum lamps emit much lower levels of UV and harmful visible spectrum radiation than other display case fluorescent bulbs, preserving the effectiveness of natamycin and thus preventing the growth of mold on grated and sliced cheeses treated with natamycin.

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Discoloration of Supermarket Cheese Displays

UV and visible spectrum radiation from supermarket fluorescent display case lighting triggers photochemical reactions that cause the bright colors of food dyes used in some cheeses to fade. While many dairy products are now sold in opaque packaging, this is not as effective as transparent containers for marketing purposes.

Cheese is light sensitive but is often packaged in clear wrapping, which leaves the cheese vulnerable to color fading and discoloration. This is most noticeable when yellow and orange cheeses are removed from their packages. The surfaces that were exposed to light have become faded, while the sides and bottoms that were against other cheese blocks and the portions that were protected by labels retain the original darker color.

Feta cheese is sometimes displayed in open containers in self-service cheese cases. When exposed to UV radiation in this way, feta will develop an off-flavor and may turn yellow.

If discoloration and color fading are combined with the effect most supermarket fluorescent lights have of emphasizing yellow and green and thus distorting the true colors of cheese displays, retail display case lighting can actually create a less than ideal cheese display.

Promolux balanced color spectrum lamps, on the other hand, reveal the true colors of cheese displays while emitting lower levels of the harmful radiation that causes colors to fade.

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Cheese Spoilage in Grocery Store Cabinets

When cheese is exposed to sunlight or to the fluorescent lighting commonly found in dairy display cases, the light initiates two chemical reactions which result in off-flavors and the loss of nutrients. 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, unsaturated fatty acids in milk lipids (milkfat triglycerides / triacylglycerols) become oxidized, producing malodorous carbonyl compounds that taste metallic or cardboardy and do not dissipate.

In as little as two hours of exposure to UV and damaging visible spectrum radiation, the fat in cheese can become rancid. While many dairy products are now sold in opaque packaging, this is not as effective as transparent containers for marketing purposes.

Unwrapped cheese displayed in self-service cheese cases, such as feta, are extremely sensitive to lipid oxidation. When exposed in this way, feta will develop an off-flavor and may turn yellow.

Factors that affect the rate of flavor change and nutrient loss are the intensity of the light, the wavelengths present in the light, the distance between the fluorescent light bulb and the cheese, the material of the container, the amount of surface area exposed to the light, the temperature of the cheese, and the duration of light exposure.

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Promolux True Color Definition Lamps

Promolux Safe Spectrum lamps emit lower levels of heat and ultraviolet radiation than regular fluorescent lamps, thus reducing the rate of these chemical reactions in cheese. Compared to other fluorescent lighting, Promolux lamps emit 86% lower UV B radiation, a shorter wavelength that penetrates and causes heating, and 52% lower UV A radiation, a longer wavelength that tends to affect surfaces.

Because Promolux lamps are designed for true color definition, they have a more balanced visible spectrum than other fluorescent lamps. The yellow and green wavelengths that are predominant in regular fluorescent lighting are the most damaging wavelengths in the visible spectrum. Promolux lamps emit a more balanced range of wavelengths, including more of the red and blue wavelengths and more moderate levels of the yellow and green wavelengths. It is impossible to create a natural light that does not have any yellow or green wavelengths, so light sources will always be damaging to some extent.

However, since Promolux lamps minimize the emission of damaging visible spectrum and UV wavelengths, using Promolux lamps will reduce shrinkage compared to the shrinkage caused by standard cheese display case lights. These savings will vary depending upon the duration of light exposure, which can vary from day to day and from hour to hour; the type of packaging; the fat content of the cheese; and how the cheese has been processed.