Inactivation of Shiga Toxin-Producing Escherichia coli in Refrigerated and Frozen Meatballs Using High Pressure Processing.

Anna C S Porto-Fett,John B Luchansky,Michelle Oliver,Lamin S Kassama,Marciauna Daniel,Yangjin Jung,Armitra Jackson-Davis

doi:10.3390/microorganisms8030360

Abstract

High pressure processing (HPP) was evaluated to inactivate Shiga toxin-producing Escherichia coli (STEC) in raw meatballs. Ground meat (>90% lean) was inoculated (ca. 7.0 log CFU/g) with a rifampicin-resistant cocktail of eight STEC strains (O26:H11, O45:H2, O103:H2, O104:H4, O111:H-, O121:H19, O145:NM, and O157:H7). Inoculated ground beef, ground veal, or a mixture of ground beef, pork, and veal were separately mixed with liquid whole eggs and seasonings, shaped by hand into meatballs (40 g each), and stored at −20 or at 4 °C for at least 18 h. Samples were then exposed to 400 or 600 MPa for 0 to 18 min. There were no differences (p > 0.05) in pathogen reduction related to the species of meat used or for meatballs that were refrigerated (0.9 to 2.9 log CFU/g) compared to otherwise similar meatballs that were stored frozen (1.0 to 3.0 log CFU/g) prior to HPP treatment. However, less time was needed to achieve a ≥ 2.0 log CFU/g reduction at 600 MPa (1 to 3 min) compared to 400 MPa (at least 9 min). This work provides new and practically useful information on the use of HPP to inactivate STEC in raw meatballs.

Highlights

Consumption of under-processed and improperly handled or stored food products contaminated with Escherichia coli O157:H7 or non-O157:H7 Shiga toxin-producing cells of E. coli (STEC) are responsible for ca. 265,000 illnesses annually, as well as ca. 3600 hospitalizations and ca. 30 deaths each year [1]
Morales et al [7] demonstrated that high-pressure processing (HPP) reduced E. coli O157:H7 levels in ground beef by 0.82 and 4.39 log CFU/g after 1 and 20 min exposures at 400 MPa, respectively; significant changes in color and texture were observed after 10 min of HPP treatment
Regardless of the type of meat used in the formulation, the state of the meat just prior to treatment via HPP, or the level of pressure applied (i.e., 400 vs. 600 MPa), longer treatment times produced a greater reduction in the levels of Shiga toxin-producing Escherichia coli (STEC)-8

Summary

Introduction

Consumption of under-processed and improperly handled or stored food products contaminated with Escherichia coli O157:H7 or non-O157:H7 Shiga toxin-producing cells of E. coli (STEC) are responsible for ca. 265,000 illnesses annually (ca. 5300 laboratory confirmed), as well as ca. 3600 hospitalizations and ca. 30 deaths each year [1]. The Food Safety and Inspection Service (FSIS) of the U.S Department of Agriculture (USDA) issued regulations stipulating that cells of serotype O157:H7 and cells of the big six non-O157 STEC serogroups are considered adulterants in non-intact beef and veal products, including ground beef and related products containing comminuted beef such as raw meatballs [3]. For these reasons, much effort has focused on developing and validating interventions to lower the occurrence and levels of cells of the seven regulated STEC serovars in food, and in beef. HPP is gaining favor and increasing use for enhancing safety and maintaining the wholesomeness of raw and ready-to-eat (RTE) red meat and poultry products [5]

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Results

Conclusion