Monthly Archives: January 2013

Dark-cutting beef

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To understand “dark-cutting beef,” it is necessary to understand how the bright red color of beef occurs. At death, the muscle attempts to maintain all normal activities. To do so, it must have energy in the form of ATP. To get ATP, it breaks down glycogen through postmortem glycolysis. A by-product of postmortem glycolysis is lactic acid. Lactic acid builds up in the muscle over a 16 to 24 hour period post-slaughter. A normal level of lactic acid (pH of 5.6) in the muscle will cause the meat… Read More →

Cause of shiny, rainbow appearance on some cured meats

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A natural phenomenon in cured meat (and some fresh meat) is the occurrence of iridescence or a rainbow appearance on the cut lean surface. Technically, this is referred to as birefringence. It is caused by the reflectance of light off of muscle proteins, and it is analogous to the color distribution produced by a prism. Muscle proteins are arranged in strands called myofilaments, which are bound together to form myofibrils. Myofibrils are bound together to form muscle fibers, which form together to form muscle bundles and finally whole… Read More →

Possible causes for white film on beef jerky

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White film on beef jerky occurs occasionally and can be of concern to customers. This was originally prepared by Dr. Jimmy T. Keeton in response to questions about this condition. Possible causes of white film on beef jerky include: Mold — The white film could be mold on the surface if the product is packaged where oxygen can get to the surface (i.e., packaged in a jar, or non-vacuumed bulk pack), not vacuum packaged, nor backflushed with nitrogen. Mold requires oxygen to grow and will not grow if oxygen… Read More →