|KULAS, MEGAN - Kansas State University|
|SWARTZ, RICHARD - Pennsylvania State University|
|SHANE, LAURA - Drexel University|
|STRASSER, HANNAH - Delaware Valley College|
|MUNSON, MADISON - Drexel University|
Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2015
Publication Date: 6/1/2015
Citation: Kulas, M., Porto Fett, A.C., Swartz, R., Shane, L., Strasser, H., Munson, M., Shoyer, B.A., Luchansky, J.B. 2015. Thermal inactivation of Shiga toxin-producing Escherichia coli cells within veal cordon bleu. Journal of Food Safety. DOI:10.1111/jfs.12188.
Interpretive Summary: Veal cordon bleu is a popular meal prepared by placing a thin slice of cheese and a thin slice of cured pork between two flattened cutlets, and then coating the resulting “turnover-type meat product” with flour, liquid eggs, and bread crumbs. Although veal cordon bleu has not caused any reported outbreaks and/or recalls in the U.S., presumably because relatively little of this product is produced/consumed and because it is likely to be cooked to well done, a similar product made with poultry has been linked with at least six outbreaks and recalls directly attributed to Salmonella. There is also a heightened concern over the comparatively greater recovery rate of STEC from veal compared with beef, as well as the recent recalls associated with veal due to pathogen contamination, coupled with the potential for poor hygiene/handling practices in plants and inadequate cooking to eliminate STEC cells within this turnover-type meat product. Thus, we evaluated time and temperature cooking regimens for lethality toward STEC inoculated onto mechanically tenderized veal cordon bleu steaks. Our results confirmed that it was possible to kill 100,000 cells of STEC by cooking veal cordon bleu steaks at 375F for at least 7 minutes per side in 45 ml of olive oil. The ability to kill STEC cells was appreciably affected by the presence/absence of breading and the volume of olive oil used.
Technical Abstract: We evaluated the fate of Shiga toxin-producing Escherichia coli (STEC) within mechanically tenderized veal cordon bleu steaks following cooking on a flat-surface, non-stick griddle. Pre-flattened veal cutlets (ca. 75 g; ca. 0.34 cm thick) were purchased from a local vendor and both faces were surface inoculated with a rifampicin-resistant cocktail (ca. 6.6 CFU/g) comprised of single strains of serotype O26:H11, O45:H2, O103:H2, O104:H4, O111:H-, O121:H19, O145:NM, and O157:H7 STEC. Following inoculation, cutlets were mechanically tenderized via one passage through a “Sir Steak” tenderizer. Next, veal cordon bleu steaks were prepared just before cooking by placing one slice of cooked deli-ham (ca. 22.2 ± 3.2 g; 11.8 cm L ' 13.5 cm W) and one slice of Swiss cheese (ca. 23.2 ± 0.5 g; 9.1 cm L ' 10.0 cm W) between two tenderized cutlets, and then hand coating the cordon bleu steaks with an all-purpose enriched pre-sifted flour. Next, flour-coated cordon bleu steaks were immersed in pasteurized liquid whole eggs followed by covering both sides of the steak with flavored bread crumbs; this processed was repeated one additional time. For each of three trials, three inoculated and tenderized cordon bleu steaks (ca. 304 ± 39 g; ca. 0.5 cm H x 12.2 cm L x 8.2 cm W) were individually cooked for 4 to 10 min per side in 45 ml of extra virgin olive oil that was pre-heated (ca. 191.5C) on a hard-anodized aluminum non-stick griddle via the use of a flat-surface electric ceramic hot plate. The internal temperature of the meat and the surface temperature of the griddle were monitored/recorded using a Type J thermocouple. The average final internal temperatures of veal cordon bleu steaks cooked for 4, 5, 6, 7, 8, 9, or 10 min were 53.5 ± 11.2, 62.1 ± 5.1, 62.3 ± 7.6, 69.0 ± 3.3, 77.3 ± 6.3, 86.0 ± 7.5, and 85.7 ± 9.1C, respectively. Cooking for 4, 5, or 6 min reduced STEC levels by ca. 1.2, 2.5, and 3.1 log CFU/g, respectively. However, cooking cordon bleu steaks for 7, 8, 9, or 10 min resulted in reductions of ca. 5.8 to 6.2 log CFU/g. These data validate that cooking tenderized veal cordon bleu for at least 7 min per side in 45 ml of olive oil on a griddle heated at ca. 191.5C is sufficient to achieve a =5-log reduction of STEC.