Commercial wash of leafy vegetables do not significantly decrease bacterial load but leads to shifts in bacterial...

Area of Science:

• Food microbiology
• Plant science
• Microbial ecology

Background:

• Ready-to-eat leafy vegetable consumption has increased, leading to foodborne illness outbreaks.
• Contamination can occur throughout the production chain, making washing a standard commercial practice.
• Understanding bacterial communities in spinach and rocket is crucial for food safety.

Purpose of the Study:

• To explore bacterial communities in spinach and rocket during commercial processing.
• To identify potential contamination events in ready-to-eat produce.
• To investigate the impact of commercial washing on bacterial load and composition.

Main Methods:

• Sampling of spinach and rocket at field, post-washing, and end-of-shelf-life stages.
• Analysis of bacterial community composition and diversity.
• Detection of specific bacteria, including E. coli.

Main Results:

• Bacterial community composition and diversity changed significantly from harvest to shelf-life.
• Washing did not reduce overall bacterial load but altered species composition.
• E. coli was detected post-washing, suggesting cross-contamination in wash water.
• Relative abundance of spoilage bacteria increased in the cold chain.

Conclusions:

• Commercial washing of leafy greens does not reduce bacterial load but can shift microbial composition.
• Cross-contamination, including E. coli, is a risk during the washing process.
• Minimally processed vegetables require stringent safety measures to mitigate microbial risks.