Thermal Inactivation of Shiga Toxin‐Producing Escherichia coli Cells within Veal Cordon Bleu

Abstract

AbstractVeal cutlets were surface inoculated with ca. 6.6 cfu/g of an eight‐strain rifampicin‐resistant cocktail of Shiga toxin‐producing Escherichia coli (STEC) (O26:H11, O45:H2, O103:H2, O104:H4, O111:H‐, O121:H19, O145:NM and O157:H7). Cutlets were mechanically tenderized and cordon bleu was prepared by adding slices of ham and cheese between two cutlets prior to batter/breading and cooking. Fully assembled cordon bleu were cooked in preheated (191.5C) extra virgin olive oil (45 mL) on a griddle. Cooking for 4, 5 or 6 min per side reduced STEC levels by ca. 1.3, 2.2 or 3.4 log cfu/g, respectively, whereas cooking for 7–10 min per side resulted in reductions of ca. ≥6.2 log cfu/g. These data validated that cooking tenderized veal cordon bleu for at least 7 min per side in 45 mL of olive oil on a griddle maintained at ca. 191.5C is sufficient to achieve an internal cordon bleu temperature of 69.0 ± 3.3C and a ≥5‐log reduction of STEC.Practical ApplicationsVeal cordon bleu is a popular meal prepared by placing a slice of cheese and a slice of cured pork between two cutlets and then coating/breading the resulting turnover‐type product. We evaluated time and temperature cooking regimens for lethality toward Shiga toxin‐producing Escherichia coli (STEC) inoculated onto mechanically tenderized multicomponent veal cordon bleu. Our results confirmed that a 5‐log reduction of STEC was achieved by cooking veal cordon bleu to an internal temperature of 69.0 ± 3.3C for at least 7 min per side on a griddle maintained at 191.5C. Reductions of ca. 1.5–3.5 log cfu/g were also achieved following cooking for 4 to 6 min per side. These data establish guidelines for cooking veal cordon bleu, which, in turn, may decrease the potential risk of STEC illnesses associated with this product if pathogens are present and if these products are undercooked or mishandled.