When beef is labeled "blade tenderized," what does that mean?
Blade-tenderized (also known as “mechanically tenderized” or “needled”) meat has been passed through a machine that punctures it with small, sharp blades or needles to break up the connective tissue and muscle fibers with the aim of making a potentially chewy cut more palatable (or an already tender cut more so). Because the blades can potentially transfer illness-causing bacteria such as E. coli from the surface of the meat into the interior, meat processed in this way should be cooked to 160 degrees (well-done) to ensure that any potential bacteria is no longer viable. Unfortunately, blade-tenderized meat can be difficult to identify because the punctures are nearly invisible to the naked eye. While the U.S. Department of Agriculture has published guidelines suggesting that all mechanically tenderized meat be labeled and accompanied by a reminder to cook the meat to 160 degrees, these do not become mandatory until January 2016. A handful of retailers, including Costco, label their tenderized beef, but if you’re concerned, you can ask your supermarket butchers to see if they can confirm the processing of their meat.
As for the effectiveness of blade tenderizing, we compared tenderized top sirloin steaks and rib-eye steaks from Costco with traditional steaks, and we found that the blade-tenderized steaks were indeed more tender when all the steaks were cooked to a safe 160 degrees. But we prefer our steaks cooked to medium-rare, and—since that isn’t advisable with blade-tenderized beef—we’ll be seeking out traditional meat.