Exploring the Idea of Using “Good” Bacteria to Prevent the Spoilage of Meat

Background

Canada has continued to make major improvements in beef safety and shelf life with advancements in how both carcasses and individual cuts of meat are handled. Even so, sporadic recalls associated with Escherichia coli (E. coli) O157 do still occur and storage life of different products continues to be variable. Lactic acid bacteria (LAB) are food safe and naturally occurring in vacuum-packaged meat. They tend to become the most common bacteria in beef that is stored for longer periods of time under vacuum packaging. Previous studies have shown that Carnobacterium maltaromaticum strain (A5) can inhibit the growth of pathogenic and spoilage bacteria in a petri dish and broth cultures at high levels. 

ObjectiveS

• Assess whether the inhibitory effect of a Carnobacterium maltaromaticum strain (A5) on pathogenic and spoilage bacteria can be reproduced with meat.

What they did

To see how C. maltaromaticum A5 strain reacted on meat, researchers introduced low levels of C. maltaromaticum A5 to steaks that had no pathogen contamination, and E. coli and Salmonella contamination. Low levels were used to keep the treatment cost effective. The steaks along with steaks that had not been inoculated with C. maltaromaticum A5 were vacuum packaged and stored at 2°C for up to 12 weeks. After 12 weeks the meat was tested for the presence of spoilage bacteria as well as other indicators of spoilage such as odour. 

What they learned

The majority of steaks that weren’t inoculated with Caronobacterium were negative for the organism. This suggests that the Carnobacterium detected in inoculated steaks were primarily from inoculation, rather than bacteria that naturally occured in the meat. The number of C. maltaromaticum A5 continued to increase as the trial went on up to some point but by the end of the trial there were no differences in in the number of spoilage bacteria between the meat that had been inoculated and the meat that hadn’t. Initially all the steaks had a very diverse group of bacteria on them but after 4 weeks spoilage bacteria began to predominate in all steaks. When tested by a consumer panel for off odour only small differences could be detected between the steaks that were inoculated and those that were not.

What it means

This suggests that at these low concentrations C. maltaromaticum A5 is unable to prevent spoilage microbes from taking over. Since C. maltaromaticum A5 was able to establish at these low levels inoculation at higher levels could be looked at in future research. If inoculation at higher amount could reduce total spoilage bacteria this would result in meat that could be stored longer without the use of preservatives.