Microfluidic droplet application for bacterial surveillance in fresh-cut produce wash waters

Foodborne contamination and associated illness in the United States is responsible for an estimated 48 million cases per year. Increased food demand, global commerce of perishable foods, and the growing threat of antibiotic resistance are driving factors elevating concern for food safety. Foodborne...

Full description

Saved in:

Bibliographic Details
Published in:	PloS one Vol. 15; no. 6; p. e0233239
Main Authors:	Harmon, J. Brian, Gray, Hannah K, Young, Charles C, Schwab, Kellogg J, Lianou, Alexandra
Format:	Journal Article
Language:	English
Published:	San Francisco Public Library of Science 09-06-2020 Public Library of Science (PLoS)
Subjects:	Antibiotic resistance Antibiotics Antibodies Applied physics Bacteria Biology and Life Sciences Bioreactors Citrobacter Commodities Contamination Control Droplets Drug resistance E coli Engineering Engineering and Technology Environmental health Escherichia coli Farm produce handling Fluorescence Food borne diseases Food contamination Food contamination & poisoning Food industry Food processing industry Food safety Foodborne diseases Health aspects Health surveillance Illnesses Incubation Laboratories Medicine and Health Sciences Methods Microbial contamination Microfluidics Optimization Pathogens Perishable foods Physical Sciences Produce industry Production management Public health Research and Analysis Methods Researchers Resistance factors Risk factors Safety and security measures Salmonella Surveillance Wash water Water analysis Water sampling United States United States > US Maryland Baltimore Maryland
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Foodborne contamination and associated illness in the United States is responsible for an estimated 48 million cases per year. Increased food demand, global commerce of perishable foods, and the growing threat of antibiotic resistance are driving factors elevating concern for food safety. Foodborne illness is often associated with fresh-cut, ready-to-eat produce commodities due to the perishable nature of the product and relatively minimal processing from farm to the consumer. The research presented here optimizes and evaluates the utility of microfluidic droplets, also termed ultra-miniaturized bioreactors, for rapid detection of viable Salmonella enterica ser. Typhimurium in a shredded lettuce wash water acquired from a major Mid-Atlantic produce processing facility (denoted as Producer) in the U.S. Using a fluorescently-labeled anti-S. Typhimurium antibody and relative fluorescence intensities, paired with in-droplet incubation, S. Typhimurium was detected and identified with 100% specificity in less than 5 h. In initial optimization experiments using S. Typhimurium-spiked sterile water, the relative fluorescence intensity of S. Typhimurium was approximately two times that of the observed relative intensities of five non-S. Typhimurium negative controls at 4-h incubation in droplets containing Rappaport-Vasiliadis (RV) broth at 37°C: relative fluorescence intensity for S. Typhimurium = 2.36 (95% CI: 2.15-2.58), Enterobacter aerogens 1.12 (95% CI: 1.09-1.16), Escherichia coli 700609 = 1.13 (95% CI: 1.09-1.17), E. coli 13706 1.13 (95% CI: 1.07-1.19), E. coli 700891 1.05 (95% CI: 1.03-1.07) and Citrobacter freundii 1.04 (95% CI: 1.03-1.05). S. Typhimurium- and E. aerogens-spiked shredded lettuce wash waters acquired from the Producer were then incubated 4 h in-droplet at 37°C with RV broth. The observed relative fluorescence of S. Typhimurium was significantly higher than that of E. aerogens, 1.56 (95% CI: 1.42-1.71) and 1.10 (95% CI: 1.08-1.12), respectively. While further optimization focusing on compatible concentration methodologies for highly-dilute produce water samples is needed, this application of droplet microfluidics shows great promise in dramatically shortening the time necessary-from days to hours-to confirm viable bacterial contamination in ready-to-eat produce wash waters used throughout the domestic and international food industry.
Bibliography:	Competing Interests: The authors have declared that no competing interests exist.
ISSN:	1932-6203 1932-6203
DOI:	10.1371/journal.pone.0233239