A new food safety treatment developed by the US department of agriculture’s Agricultural Research Service (ARS) could increase the effectiveness of conventional produce sanitisation methods.
A new methods developed by ARS microbiologist Ching-Hsing Liao involves beneficial bacteria hindering the growth of their potentially harmful counterparts.
These beneficial bacteria inhibit the growth of pathogens that survive initial physical or chemical attempts to remove them from fresh produce.
Liao identified three beneficial bacterial antagonists for use in food safety intervention. He dipped capsicum in solutions of water containing the beneficial antagonists and examined the effect on surface pathogens such as Salmonella and E. coli O157:H7.
One bacterium, known as Pseudomonas fluorescens 2-79, was particularly effective and dipping peppers in a solution of this bacterium for about two minutes halted pathogen multiplication almost entirely.
On untreated peppers, pathogen populations multiplied about 100,000 times when stored at 68 °F for two days. But treating peppers with Pf 2-79 suppressed pathogen growth. This treatment could potentially prevent pathogens from proliferating to numbers capable of causing human illness.
The dip also stopped the growth of two common spoilage bacteria and reduced the development of soft rot.
Pf 2-79 is easy to grow and can colonize several types of produce. Because it can grow at refrigeration temperatures, it could be an effective control agent for cold-tolerant pathogens such as Listeria monocytogenes and Yersinia enterocolitica.
Liao and his colleagues plan to validate the research on a larger scale. Their research will also aim to identify additional bacterial strains that could be used with Pf 2-79 to further improve produce safety and quality.
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