University of Illinois food scientist Susan Brewer found that certain preservative and flavor-enhancing solutions using sodium lactate or sodium diacetate were effective antibacterial agents also.
The find is significant because some processes of tenderising, flavor-enhancing and preserving meat can quickly spread pathogen contamination across a production line.
"A certain amount of fat makes meat juicy and tasty, but in recent years consumers have been demanding leaner and leaner cuts of meat. Processors are now using the needles that tenderize steaks and chops to inject solutions that make the meat taste better and last longer," she said.
Needles at the end of the process line inject one cut of meat after another with flavor boosters and shelf-life extenders, while a basin catches fluid that goes through the meat or runs off the surface, recycling it back into the system. Such processes can spread contamination throughout a processing line and also impregnate meat with pathogens existing on the surface of meat.
""With needle injection, organisms that exist on the outside of a piece of meat can get poked down into the meat where they're less likely to be killed if consumers like their meat on the rare side," said Brewer.
Brewer and her team conducted two studies. In the first study they contaminated the surface of meat with E. coli K12, an indicator organism for its more dangerous relative, E. coli 0157:H7, to observe the pathogen's progress as meat went through the system.
"We inoculated meat at various microbial loads, with some seriously nasty surface contamination on some pieces of meat," she said.
In the second study, they added E. coli K12 into the solution itself, experimenting with different components and combinations.
The scientists found that some solutions used to extend the shelf life of meat also were effective at killing bacteria.
"In certain solutions containing sodium lactate or sodium diacetate, bacteria cells couldn't grow and were substantiallyreduced," said Brewer. "These shelf-life enhancers definitely work, and it really doesn't make any difference whether the steak itself or the solution iscontaminated."