Quantitative model predicts implementing school cafeteria share tables will not compromise milk safety.

Area of Science:

• Food Safety
• Microbiology
• Public Health

Background:

• School share tables offer solutions for food waste and food security by enabling sharing of unopened food items like milk.
• Safety concerns regarding pathogen growth, specifically Listeria monocytogenes (L. monocytogenes), in milk on share tables hinder their implementation.

Purpose of the Study:

• To assess the risk of L. monocytogenes growth and potential listeriosis illness associated with milk cartons available on school share tables.
• To identify risk factors and evaluate mitigation strategies for ensuring milk safety on share tables.

Main Methods:

• A simulation model was developed to study L. monocytogenes in pasteurized milk, reflecting realistic low pathogen prevalence.
• Student sharing behavior was simulated over 50 school years, assessing milk safety through pathogen growth time, concentration at consumption, and listeriosis risk.
• Twenty-three what-if scenarios were analyzed, including variations in temperature management, refrigeration, and service duration.

Main Results:

• Under baseline conditions without temperature management, L. monocytogenes increased by 1 log10 after the first reservice.
• With temperature management, improved refrigeration, or shorter services, significant pathogen growth was delayed.
• L. monocytogenes concentration at consumption remained below 100 cfu/mL in most scenarios, and the predicted probability of listeriosis illness was extremely low.

Conclusions:

• The predicted risk of listeriosis from consuming milk on school share tables is minimal, even under various adverse conditions.
• Implementing share table temperature management and optimizing service durations are effective strategies for mitigating potential risks.
• This study provides an evidence base to support the safe implementation and approval of school share table practices by health departments.