An investigation into the phenomenon of cross-protection inEscherichia coliO157:H7

Rowe, M.T.; Kirk, R.B.

doi:10.1006/fmic.1998.0229

Cited by 58 publications

(26 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Acid exposure of E. coli ATCC 25922 for 1h and longer acid exposure (18h) for NCTC 12900 resulted in increased acid resistance, potentially giving a cross -protective effect against ozone treatment. Treatment of E. coli O157:H7 with acid has been reported to increase acid resistance after exposure to moderate acid environments (Kroll & Patchett, 1992;Leyer, Wang & Johnson, 1995) and was also shown to confer cross resistance to salt and heat (Rowe & Kirk, 1999). In beef processing, prior acid adaptation negatively influenced the efficacy of a 2% acetic acid decontamination treatment for reduction of E.…”

Section: Discussionmentioning

confidence: 99%

Inactivation of Escherichia coli in orange juice using ozone

Patil¹,

Bourke²,

Frias³

et al. 2009

Innovative Food Science & Emerging Technologies

112

View full text Add to dashboard Cite

This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (10 6 CFU mL -1 ) as a challenge microorganism was treated with ozone at 75-78µg mL -1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500m or 1mm sieves. Fast inactivation rates for total reduction of E. coli were achieved in model orange juice (60 seconds) and in juice with low pulp content (6 min). However, in unfiltered juice inactivation was achieved after 15-18 min. This indicated that juice organic matter interferes with antibacterial activity of gaseous ozone. The effect of prior acid (pH 5.0) exposure of E. coli strains on the inactivation efficacy of ozone treatment was also investigated. There was a strain effect observed, where prior acid exposure resulted in higher inactivation times in some cases by comparison with the control cells.However, the overarching influence on inactivation efficacy of ozone was related to the pulp content. Generally, the applied gaseous ozone treatment of orange juice resulted in a population reduction of 5 log cycles.Key words: Escherichia coli, ozone, non-thermal inactivation, acid exposure, orange juice, microbial kinetics Industrial relevance: To facilitate the preservation of unstable nutrients many juice processors have investigated alternatives to thermal pasteurisation, including unpasteurised short shelf life juices with high retail value. This trend has continued within the European Union. However within the US recent regulations by the FDA have 3 required processors to achieve a 5-log reduction in the numbers of the most resistant pathogens in their finished products. Pathogenic E. coli may survive in acid environments such as fruit juices for long periods. This study demonstrates that the use of ozone as a non-thermal technology is effective for inactivation of E. coli and acid exposed E. coli in orange juice. Information on the design of the ozone treatment for inactivation of E. coli which results into safe juice products is also among the main outputs of this work. Ozone auto-decomposition makes this technology safe for fruit juice processing.4

show abstract

Section: Discussionmentioning

confidence: 99%

Inactivation of Escherichia coli in orange juice using ozone

Patil¹,

Bourke²,

Frias³

et al. 2009

Innovative Food Science & Emerging Technologies

112

View full text Add to dashboard Cite

show abstract

“…coli O157:H7 (MAR) (Zambrano et al 1993;Rowe et al, 1999). Another stress response gene slp, which is involved in the uptake of nutrients or medium constituents (Seone et al, 1995) is also reported to be down regulated by the MAR system (Price et al, 2000) and may be another possible link to the extreme acid and heat sensitivity observed in this E. coli O157:H7 (MAR).…”

Section: Thermal Resistance In Mince-meatmentioning

confidence: 96%

Survival of antibiotic resistant and antibiotic sensitive strains of E. coli O157 and E. coli O26 in food matrices

Duffy

Walsh

Blair

et al. 2006

International Journal of Food Microbiology

View full text Add to dashboard Cite

antibiotic resistance. In yoghurt and orange juice, E. coli 0157:H7 (MAR) died off significantly faster (P < 0.05), than any of other VTEC strains examined. E.coli 0157:H7 (MAR) was also found to be significantly more heat sensitive (P <0.05), than the other VTEC strains tested. The reasons for the observed differences in survival of the different VTEC strains and the link between antibiotic resistance and survival in VTEC organisms are discussed.

show abstract

“…Leyer, Wang and Johnson (1995) recorded an acidadaptive response in E. coli O157:H7 and that the expression of this system augments survival in acidic food products such as apple cider and fermented sausage. Treatment of E. coli O157:H7 with acid has been reported to increase acid resistance after exposure to moderate acid environments (Leyer et al, 1995) and was also shown to confer cross resistance to salt and heat (Rowe & Kirk, 1999). There is potential for survival of pathogenic E. coli in acid environments and there may be effects of prior acid adaptation on resistance to sonication treatment, which has been identified as a gap in current knowledge (Salleh-Mack & Roberts, 2007).…”

Section: Introductionmentioning

confidence: 93%