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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #314440
Title: Efficacy of plant derived compounds against Eschericha coli 157:H7 during flume-washing and storage of organic leafy greens

Author
item DENTON, JORDON - Oklahoma State University
item RAVISHANKAR, SADHANA - University Of Arizona
item Friedman, Mendel
item JARONI, DIVYA - Oklahoma State University

Submitted to: Journal of Food Processing and Preservation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2015
Publication Date: 6/18/2015
Publication URL: http://dx.doi.org/10.1111/jfpp.12523
Citation: Denton, J.J., Ravishankar, S., Friedman, M., Jaroni, D. 2015. Efficacy of plant derived compounds against Eschericha coli 157:H7 during flume-washing and storage of organic leafy greens. Journal of Food Processing and Preservation Research. doi: 10.1111/jfpp.12523.

Interpretive Summary: In a collaborative study with the Departments of Animal Science, University of Oklahoma, Stillwater and the School of Animal and Biomedical Sciences, University of Arizona, Tucson, we evaluated the antimicrobial efficacy of plant-derived compounds (cinnamaldehyde, carvacrol, and citral) against Escherichia coli O157:H7 during the flume-tank-washing process and subsequent storage of organic leafy greens. Organic fresh produce is gaining popularity with the consumers, including minimally processed, bagged leafy greens. However, recent outbreaks of foodborne illnesses associated with organic leafy greens have introduced a need to develop better mitigation strategies. Sanitizers are routinely used during flume-washing of leafy greens. However, use of synthetic decontaminants is prohibited for organic fresh produce. Additionally, commonly used sanitizers such as hydrogen peroxide and peroxyacetic acid have not proven to be as effective. Plant-derived antimicrobials are therefore being considered by the organic fresh produce industry as alternatives to these sanitizers. This study assessed the efficacy of three plant-derived treatments against Escherichia coli O157:H7 on four types of organic leafy greens in flume-tank wash-water. Results from the study indicate that plant-derived compounds can serve as effective natural antimicrobials against E. coli O157:H7 for washing organic leafy greens before they are bagged and shipped for retail.

Technical Abstract: Organic baby and mature spinach, and romaine and iceberg lettuce, inoculated with a cocktail of E. coli O157:H7, were washed for 1 or 2 minutes in 0.1, 0.3 and 0.5% concentrations of the compounds and stored at 4 ºC. Pathogen survivors were enumerated on days 0, 1, and 3. Significant (P<0.05) reductions in E. coli O157:H7 populations were observed with all three compounds compared to the controls. Carvacrol at 0.5% was most effective on each leafy green, reducing pathogen populations to undetectable levels on day 0. All the compounds showed better antimicrobial efficacy at higher concentrations and continued this effect during the 3-day storage. Washing the leafy greens without the natural antimicrobialsfor more than 1 minute did not significantly affect E. coli O157:H7 populations.