Color of Fresh Meat in Supermarket Display Cases

The color of fresh meat in supermarket display cases forms a first impression that strongly influences consumers’ selection of fresh meat. The pigment myoglobin which determines the color of fresh meat undergoes various chemical reactions to form other pigments. These reactions are triggered by light, heat, and oxygen availability.

Temperature and Fresh Meat Color in Supermarket Meat Cabinets

Beef displayed under Promolux lamps and regular fluorescent lights with a Promolux filter, which both block UV radiation, maintained virtually the same bright red color, fresh smell, low bacterial count, and low levels of metmyoglobin as beef stored in the dark, while beef displayed under a standard supermarket fluorescent light became brown and decomposed rapidly after only 12 days.

Temperatures above -1.5°C (29.3°F) encourage the exponential growth of bacteria, which consume the oxygen near the surface of the meat, hastening the creation of the brown pigment metmyoglobin.

Even small temperature increases have a profound effect on the growth of bacteria which leads to meat spoilage. Regular display case lighting emits heat, as well as radiation that is transformed into heat when it is trapped within the meat’s packaging, and can cause the surface temperature of displayed meat to be much higher than the temperature of the refrigerated display case.

pH and Fresh Meat Color in Grocery Store Meat Cabinets

The pH of fresh meat naturally falls from about 7 to about 5.5 over a period of 24 hours after the animal is slaughtered. However, genetic problems or mishandling of the animal or carcass can affect the pH of the muscle tissue adversely.

If the pH drops too rapidly or is at a very low level, the meat becomes pale, soft, and exudative (PSE), and if the pH does not drop at all or is at a high level, the meat becomes dark, firm, and dry (DFD). Dryness hinders the muscle tissue’s ability to absorb oxygen and bloom. These terms are often used to describe problems with pork.