Swiss Cheese Model of food safety incidents: Preventing foodborne illness through multiple layers of defence

This study aims to discuss the use of multiple layers of defence to prevent foodborne illness in restaurants. A defence model was developed based on Reason's Swiss Cheese Model. Reason's model was extended by adding the concept of Hazard Analysis and Critical Control Points, as well as Five Keys to Safer Food. The defence system was divided into seven layers of defence: 1) adequate facilities and 2) training as administrative controls; 3) safe ingredients and water; 4) environmental hygiene; 5) personal and food hygiene and 6) safe food temperature as behavioural controls; and 7) control and systems. The hypothesis was that the layers would act as barriers to prevent hazards from causing losses. To test the model, a dataset (secondary data) of food safety assessments from 1536 different restaurant establishments in Brazil was used. A checklist of 51 items was organised into seven layers of defence system. The model was tested with a Partial Least Square Structural Equation Model. Errors in administrative controls (facilities and training) led to errors in behavioural controls. A 'cascade effect' was observed where errors in distal behavioural controls (safe ingredients and water and environmental hygiene) impacted proximal controls (personal and food hygiene and; safe food temperature) and system controls. It was discussed how latent conditions and active failures can string together and cause a foodborne illness incident. The Swiss Cheese Model of food safety incidents is proposed as a new perspective for food safety. This model can be used for risk management and food safety education.