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Published Articles from USDA ARS National Program 108: Food Safety
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Title: Effects of temperature and storage time on resting populations of Escherichia coli 0157:H7 and Pseudomonas flurorescens in vitro
Authors: Olanya OM, Ukuku DO, Niemira BA
Journal: Food Control
Accepted date: 2013 Nov 2
Interpretive summary: An understanding of how microbes interact in pure and mixed cultures is crucial for determining how harmful pathogens might be controlled by applications of non-pathogens. Escherichia coli O157:H7 is a human pathogen commonly found on meats, fruits and vegetables. We determined how the biocontrol microbe Pseudomonas fluorescens changed the survival and growth of the pathogen. Tests were conducted: 1) with each organism alone or together; 2) on various growth media; 3) at different temperatures; 4) and for various lengths of time in storage. Both bacteria showed a similar response to temperature, with total numbers generally increased at temperatures of 25 deg C and 37 deg C, with little growth observed at 5 deg C or 15 deg C. When both bacteria were grown together, the biocontrol organism suppressed the pathogen. The degree of suppression depended on the specific growth media, the storage temperatures, and the length of time in storage. This research will be useful in designing protocols that rely on biocontrol organisms to suppress pathogens on fresh and fresh-cut produce. Applications of this research may be most significant in addressing transitory temperature abuse conditions, such as during transportation of leafy green produce from fields to processing sheds.
Publication date: 2014 May
Volume: 39
Pages: 128-34