Fresh Beef Bacteria in Grocery Store Meat Cabinets
The microorganisms that attach rapidly to fresh beef and are primarily responsible for beef spoilage in grocery store meat cabinets are psychrotrophic bacteria, meaning those that are able to grow in cold temperatures, and tend to be in the genus Pseudomonas. While these bacteria are not harmful per se, they contribute to the discoloration and spoilage of beef by accelerating the oxidation of myoglobin to myoglobin, the pigment that causes fresh meat to look brown, reducing the shelf life of fresh beef to 2 to 3 days. Eighty percent of Canadian beef is sold domestically and internationally in vacuum packages, which are vulnerable to spoilage by lactic acid bacteria.
In most cases, the bacteria are only present on the surface of the meat, in the outer few millimeters. The exceptions are ground beef, where the grinding process spreads the bacteria throughout the meat, and highly spoiled beef