Penetration of surface-inoculated bacteria as a result of hydrodynamic shock wave treatment of beef steaks.
The top surface of the raw eye of round steaks was inoculated with either green fluorescent protein (GFP)-labeled Escherichia coli (E. coli-GFP) or rifampin-resistant E. coli (E. coli-rif). Cryostat sampling in concert with laser scanning confocal microscopy (LSCM) or plating onto antibiotic selective agar was used to determine if hydrodynamic shock wave (HSW) treatment resulted in the movement of the inoculated bacteria from the outer inoculated surface to the interior of intact beef steaks. HSW treatment induced the movement of both marker bacteria into the steaks to a maximum depth of 300 microm (0.3 mm). Because popular steak-cooking techniques involve the application of heat from the exterior surface of the steak to achieve internal temperatures ranging from 55 to 82 degrees C, the extent of bacterial penetration observed in HSW-treated steaks does not appear to pose a safety hazard to consumers.
Lorca
T A
TA
Department of Food Science and Technology, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg 24060-0418, USA.
Pierson
M D
MD
Claus
J R
JR
Eifert
J D
JD
Marcy
J E
JE
Sumner
S S
SS
D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003296:Cooking / Q000379:methods; D019453:Escherichia coli O157 / Q000502:physiology*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins; D008460:Meat / Q000032:analysis / Q000382:microbiology*; D018613:Microscopy, Confocal; D012293:Rifampin / Q000494:pharmacology
D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D012293:Rifampin