Salmonella is ranked as the top of the foodborne bacterial outbreaks responsible for 1,027,561 illnesses, 19,336 hospitalizations, and 378 deaths each year in the United States (Centers for Disease Control, 2018).
The current official FDA method for testing contamination in leafy greens is time consuming and labor intensive. It involves pre-enrichment, selective enrichment, plating on selective media, and subsequent biochemical and serological identification of microbes, often taking up to 4 days for results. As a result, the industry is moving towards adopting molecular analysis methods, like PCR. However, these methods still require time-consuming pre-enrichment steps before PCR, limiting the overall time savings. Rapid target enrichment is needed since produce is perishable and holding product for test results shortens shelf-life.
To this aim, researchers at the US Department of Agriculture (USDA ARS) paired the Concentrating Pipette as a means to concentrate a 3-hour enrichment for detection of salmonella from a variety of leafy green products, paired with PCR (PathogenDX) for same day results. They compared this testing with the standard FDA bacterial analytical manual (BAM) Method.
Conclusions:
- A 3-hour enrichment with concentration detected 98% of Salmonella from Romaine lettuce.
- A 6-hour enrichment detected 100% of Salmonella from Romaine lettuce at 6 CFU/25 g.
- Total analysis time was between 8 and 11 hours.
Read the Paper
Rapid detection of Salmonella enterica in leafy greens by a novel DNA microarray-based PathogenDx system - Hsin-Bai Yin, et al. Food Microbiology, Volume 107, October 2022
