Researchers in the US are working on how to make steaks more consistently tender and some of their discoveries have already been put to use by the meat industry.

Agricultural Research Service (ARS) scientists in Nebraska noticed meat is tender after slaughter, then toughens before starting to become tender again. Accordingly, the scientists believe steaks shouldn’t be sold before they’ve aged for 14 days, to make sure the meat has undergone maximum tenderisation. A majority of beef processors are already following this procedure, the ARS said.

The researchers also discovered the enzyme µ-calpaina and the variation of the protein called calpastatin, both of which have a major impact on meat tenderness. Calpastatin determines how much calpain is active and how tender the steak will be. Since calpain requires calcium for activity, the team has developed a process for injecting calcium into meat in order to make it tender.

The scientists are also studying cattle genetics and comparing the sequences of genes that produce calpain in both tender and tough cattle. They have released a DNA test that accurately identifies which cattle will likely provide tender steaks, so producers can use those animals for breeding.

The Agricultural Research Service is the US Department of Agriculture’s chief scientific research agency.