An Agent-based Model of Food Safety Practices Adoption Tim Verwaart and Natalia I. Valeeva

Food safety risk in animal products Many producers (farmers) Only a few processors Long-term relationships Producers have an interest to motivate their suppliers to take measures that reduce food safety risk

Models of economic incentives have been applied: Principal / agent theory Risk aversion

Producers’ intentions and actions depend on Economic motives AND Information Attitudes Professional competence Social norms

Diversity in attitudes toward Quality systems Food safety Animal welfare Financial incentives Risk AND Diverse sensitivity to social norms

Theory of planned behavior (Ajzen 1991) Attitudes Norms Perceived behavioral control Reasoningintention Action

Application The adoption by farmers of measures to reduce mastitis incidence in dairy cattle Mastitis is a highly relevant problem, and an advantage for ABM is the availability of a host of technical and behavioural data

Effects of mastitis: Product Bacteriological quality of milk Processability for dairy products Quality for consumption Food safety risk Process Production losses Veterinary cost

Farmers can reduce the risk of mastitis incidence by taking prevention measures Example of such a measure: wearing milkers’ gloves during milking reduces the somatic cell count (an indicator of mastitis in milk) by 7 % This example is used for a first test of the model

Application of the ABM What is the combined effect of policies to motivate farmers to take prevention measures? Policies: Penalty systems, based on somatic cell count Information campaign, awareness Taking network effects (norms) into account

Attitudes toward prevention measures Depend on subjective beliefs about the effects that the measures bring about Beliefs about prevalence reduction and associated economic effects and penalties are reinforced by information campaigns

Farmers are modeled to be diverse with respect to Openness to information Economic motivations Preference for quality / animal welfare Risk attitude Sensitivity to social norms

The model AE2011MastitisChainModel.nlogo AE2011MastitisChainModel.nlogo

Sensitivity analysis: parameters to which outputs are most sensitive Output: Number of food safety actions Output: number of penalties Output: average somatic cell count Prev. reductionPenalty thresholdE(prevalence) Additional costE(prevalence)Prev. reduction Expected savingPrev. reductionExpected saving Comm. intensitycv(prevalence)Additional cost PBC thresholdExpected savingComm. Intensity OpennessAdditional costPBC threshold

Results: effect of communication intensity *) *) no network influence taken into account

Results: effect of quality preference *) *) no network influence taken into account

Results: effect of network influence

Conclusion In addition to economic incentives, farmers may be motivated by quality preferences and social norms to implement food safety measures The joint effects of those factors and the diversity of farmers’ sensitivity to the factors should be taken into account in food safety policies An agent-based model can clarify the possible outcomes of food safety policies under diverse farmers’ preferences and network influence

Current and future work Simultaneous implementation of packages of measures More realistic network structures Calibration to actual data Application to different food safety risks, e.g. antibiotics, EHEC

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