Cost-effective monitoring of dioxins in agri-production chains

Dioxins are important chemical pollutants due to their high toxicity to human health even at very low concentrations. From all possible human exposure pathways, food ingestion is the major route with food products of animal origin as the main contributors. Feed ingredients and/or additives used in compound feed for livestock production have been a main cause of various food dioxin incidents in recent decades. These incidents resulted into large financial implications due to recalls and trade disruptions. Monitoring dioxins in feed and food products is deemed crucial when aiming at reducing human dioxin exposure with time as well as when preventing and diminishing the salient financial impact of dioxin incidents in agribusiness along the food chain. However, economic aspects embedded in the practical assessment and implementation of dioxin monitoring schemes along the food chain have not yet been analysed in the scientific literature. Hence this dissertation aims to analyse the cost-effectiveness of schemes for monitoring dioxins along the food chain by 1) assessing the financial impact of a dioxin incident in the food chain, 2) determining the cost-effectiveness of monitoring dioxins at a single control point along the food chain 3) determining the cost-effective allocation of resources for monitoring dioxins at different stages of the food chain, and 4) determining the cost-effective allocation of resources at one stage of the food chain considering incoming ingredients and final products.

Chapter 2 aimed to quantify the financial consequences of a milk-dioxin crisis on the stages of the dairy chain involved. Results obtained based on the assumption of the worst-case scenario in which the entire daily production of each business unit from feed supplier to milk processor is contaminated, show that the financial impact of a dioxin incident would be €141.2 million. The stages of the chain that contributed most to the total net costs are the milk processor (76.9%) and the dairy farm (20.5%). In case the moment of detection was reduced from 2 weeks to 3 days after initial contamination, the estimated total financial impact decreased to €10.9 million. This result emphasizes the importance of an early detection of the contamination in decreasing the number of food businesses involved and lowering the total financial impact value.

Chapter 3 assessed the costs and effectiveness of bulk milk dioxin monitoring in milk trucks to optimize the sampling and pooling monitoring strategies aimed at detecting at least one contaminated farm out of 20,000 at a target dioxin concentration level. Two optimization models were built using linear programming. The first model aimed to minimize monitoring costs subject to a minimum required effectiveness of finding an incident, whereas the second model aimed to maximize the effectiveness for a given monitoring budget. Incidents with different numbers of contaminated farms and concentrations were simulated. The results show that monitoring with 95% probability of detecting one contaminated farm with 2 pg TEQ/g fat costs €2.6 million per month. At the same level of effectiveness, a 73% cost reduction is possible when aiming to detect an incident where 2 farms are contaminated at a dioxin concentration of 3 pg of toxic equivalents/g of fat (EC maximum level). With a fixed budget of €40,000 per month, the probability of detecting an incident with a single contaminated farm at a dioxin concentration equal to the EC action level is 4.4%. This probability almost doubled (8.0%) when aiming to detect the same incident but with a dioxin concentration equal to the EC maximum level.

In Chapter 4 a decision support tool (optimization model) is developed to determine cost-effective monitoring schemes for detecting and tracing a dioxin contamination over four control points (i.e. at the supplier of fatty feed ingredients, the feed mill, the slaughterhouse and the fat melting facility) along the pork chain. The cost-effective allocation of resources for detecting and tracing the dioxin contamination from an integrated chain approach (i.e. considering all control points) focuses on monitoring at the feed mill, followed by the supplier of fatty feed ingredients and - to a lesser extent - by the slaughterhouse. The number of contaminated feed mills, the frequency of dioxin contaminations, the required level of effectiveness, and the cost of screening are main factors driving the total monitoring costs. Sharing the responsibility of monitoring dioxins within control points along the chain largely reduces the total monitoring costs. In each of the evaluated scenarios, the total costs of monitoring dioxins at individual control points are larger than the costs resulting from an optimal allocation of resources among all control points integrated in one overarching chain monitoring scheme. These results elicit the economic benefits of a chain approach to monitoring dioxins over an approach where each chain actor independently monitors dioxins.

Chapter 5 determined cost-effective strategies for monitoring dioxins at the feed mill, in order to prevent dioxin contaminations in compound feed entering the poultry production chain. Results showed that monitoring dioxins in a combination of feed ingredients (i.e., Wheat and Corn) results into a high level of effectiveness of preventing elevated levels of dioxins in the compound feed (96.2%) at lower total costs (20% less) compared to the costs related to the 100% effective monitoring in charges of compound feed. Ingredients with dioxin concentrations above ML dioxins levels but with a low inclusion rate in the feed formulation are not detected by monitoring dioxins in compound feed as a result of the dilution effect.

Chapter 6 provides a synthesis of the results obtained in the previous Chapters and discusses these findings with respect to existing literature. This chapter also presents a critical discussion of methodological issues regarding data availability and modelling approaches used to analyse the data. This is followed by a discussion about the implications of the findings for policy makers as well as for food safety managers in agri-food business, and topics for further research that go in line with this dissertation. The main conclusions of this dissertation are the following:

• There is financial room for monitoring dioxins along the Dutch dairy chain (between €500.4 thousand and €28.8 million per year) suggested by the size of the direct financial losses of a dioxin incident in the dairy chain (Chapter 2).

• Monitoring bulk milk with 95% probability of detecting contamination levels as low as 2 pg TEQ/g fat requires resources of approximately €2.6 million/month (Chapter 3).

• Testing dioxins levels in aggregate samples rather than in individual samples is a valid strategy for reducing monitoring costs. However, pooling strategies must take into account the target dioxin concentration in individual samples, in order to avoid dilution of dioxin levels and to ensure the proper detection of dioxin contamination (Chapter 3).

• Focusing monitoring efforts at feed mills to tackle a dioxin contamination in the food chain is the cost-effective solution of monitoring dioxins for the whole pork chain (Chapter 4).

• Monitoring dioxins in an integrated chain approach rather than in an independent chain actor approach has large economic benefits for the whole pork chain (Chapter 4).

• For all evaluated contamination scenarios, monitoring dioxins at the feed mill stage contributes, on average, 90% to the total effectiveness of the optimal monitoring schemes (Chapter 4).

• It is cost effective to focus dioxin monitoring efforts in earlier rather than later stages of the pork and poultry chain, when a dioxin contamination originates from a source early in the chain (Chapter 4 and 5).

• Elevated levels of dioxins in compound feed not only depend on the concentration of dioxins in feed ingredients but also on the inclusion rate of the ingredients in the compound feed (Chapter 5).