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Sulfite Residues in Restaurant Salads.
Laura B Martin1, Julie A Nordlee1, Steve L Taylor1
1Food Research Institute, Department of Food Microbiology and Toxicology, and Department of Food Science, University of Wisconsin, 1925 Willow Drive, Madison, Wisconsin 53706.
Journal of Food Protection
|April 10, 2019
Summary
Sulfiting agents in restaurant salads can pose risks to asthmatics. Studies show treated lettuce can retain high sulfite levels, while restaurant salads surveyed had minimal residues.
Area of Science:
- Food Science and Technology
- Public Health
- Analytical Chemistry
Background:
- Sulfiting agents are used to prevent enzymatic browning in restaurant salads.
- These agents, primarily sulfur dioxide (SO2) equivalents, can be a health hazard for sulfite-sensitive individuals, particularly asthmatics.
- Understanding residual sulfite levels in food is crucial for consumer safety.
Purpose of the Study:
- To quantify residual sulfite levels in chopped lettuce treated with commercial salad fresheners.
- To determine the impact of recommended and excessive usage of sulfiting agents.
- To assess the prevalence of sulfites in commercially prepared salads from restaurants.
Main Methods:
- Analysis of total SO2 equivalents in chopped lettuce treated with a commercial salad freshener at recommended and higher concentrations.
- Quantification of residual sulfites in coleslaw prepared using a standard commercial formulation.
- Survey of sulfite residue levels in various salads (lettuce, coleslaw, potato salad) from local and national restaurants.
Main Results:
- Lettuce treated at the recommended level (1 tbsp/gallon) contained up to 963 mg/kg total SO2 equivalents, primarily free SO2.
- Overuse of salad fresheners led to progressively higher retained sulfite levels.
- Coleslaw formulation contained 350 mg/kg total SO2.
- Restaurant salads surveyed showed significantly lower sulfite residues compared to treated samples, suggesting limited use.
Conclusions:
- Commercial salad fresheners can lead to substantial residual sulfite levels in treated produce.
- Potential health risks exist for sulfite-sensitive asthmatics due to sulfites in restaurant salads.
- The surveyed restaurant salads generally contained minimal sulfite residues, indicating infrequent or no use of these agents.
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