The ineffectiveness of organic acids, freezing and pulsed electric fields to control Escherichia coli O157:H7 in beef burgers

Abstract

Aims: The objective of this study was to investigate the potential value of individual and combined applications of some GRAS (generally regarded as safe) additives with freezing and pulsed electric field (PEF) application, in reducing the risks associated with the presence of E. coli O157:H7 in beef burgers. Methods and Results: Beef burgers, trimmings and filter paper were inoculated with E. coli O157:H7 and subjected to a range of chemical and physical treatments. Sequential application of 2% (v/v) lactic acid and freezing (at ) 20°C for 2 h) resulted in a decrease of approximately 6 log 10 cfu cm )1 in E. coli O157:H7, but only on filter paper. All other treatments were ineffective. Conclusions: Currently available methods for controlling E. coli O157:H7 in beef burgers during production are ineffective. Significance and Impact of the Study: Further research is needed to develop controls for E. coli O157:H7 during beef burger production.

Postharvest intervention technologies for safety enhancement of meat and meat based products; a critical review

“…Several studies reported contradictory findings regarding the use of PEF in meat and meat products (Keklik et al 2010). In this context, Bolton et al (2002) stated that use of pulse electric field was not effective in controlling E. coli O157:H7 growth in beef. The reason behind that incapability may be due to low voltage and high protein and fat contents of beef.…”

Combined high pressure–sub-zero temperature processing of smoked salmon mince: phase transition phenomena and inactivation of Listeria innocua

“…No significant inactivation nor sub-lethal injury of Listeria innocua was observed. The absence of microbial inactivation during conventional freezing has been reported for various micro-organisms (Bolton et al, 2002;Dykes & Moorhead, 2001;Moorhead & Dykes, 2002;Novak & Juneja, 2003).…”

Microbial inactivation by pressure-shift freezing: effects on smoked salmon mince inoculated with Pseudomonas fluorescens, Micrococcus luteus and Listeria innocua

“…Bolton et al (2002) studied the inactivation of E. coli O157:H7 by freezing beef burgers (at À20 C for 2 h). No significant reduction of bacterial counts was observed.…”