Aggregative Sampling Performs Similar to Composite Produce Samples to Recover Quality and Safety Indicators...

Area of Science:

• Food Microbiology
• Agricultural Science
• Food Safety Engineering

Background:

• Traditional food safety sampling methods for leafy greens can be destructive and may not fully represent microbial contamination.
• Developing non-destructive, representative sampling techniques is crucial for accurate food safety assessments in leafy green production.

Purpose of the Study:

• To compare the efficacy of aggregative sampling using polymer cloth swabs against traditional produce tissue grab sampling for recovering aerobic bacteria, total coliforms, and generic Escherichia coli from romaine lettuce.
• To evaluate aggregative sampling across various stages of romaine lettuce production, including preharvest, in-harvest, and postharvest.

Main Methods:

• Aggregative swabs and produce tissue grab samples were collected from commercial romaine lettuce at different growth and processing stages.
• Microbial analysis focused on quantifying aerobic bacteria, total coliforms, and generic Escherichia coli (E. coli) using established enumeration techniques.
• Sampling included preharvest, in-harvest (harvester chute, bin tops, harvester gloves, field trims), and postharvest (head exteriors and interiors).

Main Results:

• Preharvest, aggregative swabs yielded higher aerobic bacteria but lower coliforms than grab samples.
• In-harvest, swabs and harvester gloves showed higher aerobic bacteria recovery compared to field trims and bin tops.
• Postharvest, no significant differences in aerobic bacteria or total coliform recovery were observed between aggregative sampling methods and grab samples for both exterior and interior head surfaces.

Conclusions:

• Aggregative sampling using polymer swabs demonstrates comparable performance to traditional produce grab sampling for recovering key microbial indicators in leafy greens.
• The findings support the potential of aggregative sampling as a viable, non-destructive alternative for food safety monitoring in leafy green production.
• Further investigation into aggregative sampling for specific pathogen recovery in leafy greens is warranted.