Inactivation of Shiga toxin-producing cells of Escherichia coli in refrigerated and frozen meatballs using high pressure processing

Authors: Porto-Fett, Anna; JACKSON-DAVIS, ARMITRA - Alabama A & M University; KASSAMA, LAMIN - Alabama A & M University; DANIEL, MARCIANNA - Alabama A & M University; OLIVER, MICHELLE - Alabama A & M University; Jung, Yang Jin; Luchansky, John

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2020
Publication Date: 3/3/2020
Citation: Porto Fett, A.C., Jackson-Davis, A., Kassama, L., Daniel, M., Oliver, M., Jung, Y.N., Luchansky, J.B. 2020. Inactivation of Shiga toxin-producing cells of Escherichia coli in refrigerated and frozen meatballs using high pressure processing. Microorganisms. https://doi.org/10.3390/microorganisms8030360.
DOI: https://doi.org/10.3390/microorganisms8030360

Interpretive Summary: Over the past 20 years there have been numerous recalls and several illnesses linked to improperly cooked, handled, and/or stored ground beef and to a much lesser extent ground veal, as well as a recent outbreak and recalls linked to meatballs, due to certain serotypes of Escherichia coli that produce a potent toxin (aka Shiga toxins). Thus, we evaluated HPP as a non-thermal intervention to lower pathogen presence and load of Shiga toxin-producing Escherichia coli (STEC) in raw meatballs. In general, the longer the time that meat containing STEC was subjected to pressure, the great the inactivation of the pathogen. Reductions in STEC levels for meatballs that were maintained at 4degC or frozen prior to HPP treatment ranged from 10 to 1000 cells per gram of meat when applying pressures of 400 or 600 MPa for up to 18 min. This is significant given that STEC levels typically would be low in raw ground beef and ground veal and given that additional lethality will be achieved by subsequent cooking. Lowering the recovery rate and pathogen levels in (raw) meatballs by HPP will presumably also lower the public health risk from STEC. As a clean-label intervention, HPP provides producers and processors with an effective non-thermal option to ensure safety, enhance quality, and extend the shelf life of red meat and poultry products.

Technical 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 -20degC or at 4degC 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 meat