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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #392337
Research Project: Intervention Strategies to Mitigate the Food Safety Risks Associated with the Fresh Produce Supply Chain

Location: Environmental Microbial & Food Safety Laboratory

Title: Rapid detection of Salmonella enterica in fresh produce by a novel microarray-based PathogenDx system

Author
item Yin, Hsin Bai
item CHEN, CHI-HUNG - Orise Fellow
item KATCHMAN, BENJAMIN - Pathogendx
item NEWLAND, CORY - Pathogendx
item MAY, MELISSA - Pathogendx
item Patel, Jitu

Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2022
Publication Date: 6/30/2022
Citation: Yin, H., Chen, C., Katchman, B., Newland, C., May, M., Patel, J.R. 2022. Rapid detection of Salmonella enterica in fresh produce by a novel microarray-based PathogenDx system. Food Microbiology. 107. Aricle 104086. https://doi.org/10.1016/j.fm.2022.104086.
DOI: https://doi.org/10.1016/j.fm.2022.104086

Interpretive Summary: Fresh produce contaminated with harmful bacteria may cause human illnesses upon consumption as it is often consumed raw with minimal or no kill step to eliminate harmful bacteria. Rapid detection of these bacteria in fresh produce is required before it reaches the retail market or consumers to minimize illnesses. A microarray-based bacterial detection method was optimized with pre-enrichment and sample concentration steps to detect low contamination level of Salmonella in fresh produce. From fresh produce samples (n=205) inoculated with 6 CFU/25 g; 100%, 98%, 90%, and 82% of Romaine lettuce, Iceberg lettuce, kale, and spinach samples were detected after 6 h of pre-enrichment. The total analysis time required for these methods was about 8-11 h, in contrast to 4-5 days required for FDA standard methods. This novel method may be helpful to processors for rapid detection of Salmonella in fresh produce.

Technical Abstract: The diverse matrices pose great challenges for rapid detection of low Salmonella level in fresh produce. The applicability of microarray-based PathogenDx system for detecting low contamination of Salmonella Newport from fresh produce was evaluated. A pre-PCR preparation protocol including enrichment in universal pre-enrichment broth for 3 h followed by sample concentration using a concentrator or 6 h enrichment without a concentration step was used for detecting S. Newport (~ 6 CFU/25 g) from fresh produce. Among 205 samples tested, 98%, 93%, 76%, and 60% of Romaine lettuce, Iceberg lettuce, kale, and spinach samples were detected after 3 h of enrichment with sample concentration. After 6 h of enrichment, 100%, 98%, 90%, and 82% of Romaine lettuce, Iceberg lettuce, kale, and spinach samples were successfully detected. The FDA bacterial analytical manual (BAM) method detected all spiked produce samples at 100%. The overall analysis time of this methodology was between 8-11 h, including all pre-enrichment and concentration steps, in contrast to 4 to 5 days required for BAM method. The system correctly identified all 108 Salmonella strains and 35 non-Salmonella strains used in the study. This novel approach may be used for rapid detection of Salmonella in fresh produce.