Real-time bioluminescence analysis of Escherichia coli O157:H7 survival on livestock meats stored fresh, cold, or frozen

Authors: PARK, SEONG - Mississippi State University; WHITE, SHECOYA - Mississippi State University; STEADMAN, CHRISTY - Mississippi State University; CAVINDER, CLAY - Mississippi State University; WILLARD, SCOTT - Mississippi State University; RYAN, PETER - Mississippi State University; FEUGANG, JEAN - Mississippi State University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2018
Publication Date: 10/22/2018
Citation: Park, S., White, S., Steadman, C., Cavinder, C., Willard, S., Ryan, P., Feugang, J. 2018. Real-time bioluminescence analysis of Escherichia coli O157:H7 survival on livestock meats stored fresh, cold, or frozen. Journal of Food Protection. 81(11):1906-1912. https://doi.org/10.4315/0362-028X.JFP-18-207.
DOI: https://doi.org/10.4315/0362-028X.JFP-18-207

Interpretive Summary: The complete eradication of bacteria contamination from meats and meat products of various animal sources remains a consumer health concerns. In addition, national and international transportations of various meats required additional precaution of meat packaging and awareness of bacteria contamination and behavior to reduce the risks of foodborne illness. The attainment of a such objective necessitates the development of new approaches to study bacteria growth and rapid detection on meat before arrival to markets. Here we used real-time monitoring, in addition to routine evaluation tests, to assess foodborne bacterial growth in ground horse, beef, and pork meats maintained under various storage conditions (room temperature, refrigerated or frozen). Findings indicated real-time imaging as a useful research tool for real-time monitoring of bacterial growth and survival in various stored livestock meats. The dependence of E. coli growth on meat substrate (fat or lean) and storage conditions may be used as part of an effective antibacterial approach for the production of safe ground horse, beef, and pork meats.

Technical Abstract: Various levels of E. coli O157:H7 carrying the luxCDABE operon, which allows the cells to emit bioluminescence, were used to inoculate meat samples that were then stored at room temperature for 0.5 day, at 4oC (cold) for 7 or 9 days, or -20oC (frozen) for 9 days. Real-time bioluminescence imaging (BLI) of bacterial growth was used to assess bacterial survival or load. Ground horse meat BLI signals and E. coli levels were dose and time dependent, increasing during room temperature and -20oC storage, but stayed at low levels during 4oC storage. No bacteria survived in the lower level inoculum groups (10e1 and 10e3 CFU/g). With an inoculum of 10e7 CFU/g, pork meats had higher BLI signals than did their beef counterparts, displaying decreased BLI signals during 7 days storage at 4oC. Both meat types had higher BLI signals in the fat area, which was confirmed with isolated fat tissues in the beef meat. Beef lean and fat tissues contrasted with both pork fat and lean tissues, which had significantly higher BLI signals and bacterial levels. BLI appears to be a useful research tool for real-time monitoring of bacterial growth and survival in various stored livestock meats.