Raw drinking milk: when potential health benefits face the foodborne pathogens – a risk-benefit study

Introduction: Milk is a highly nutritious food, and currently there is a considerable debate on the potential health benefits of consumption of raw milk (RM) compared to pasteurized milk (PM). Claimed health benefits are e.g. “higher nutritional value”, especially regarding vitamins, “beneficial microflora” as probiotic bacteria, and “allergy prevention”. However, several human pathogens can be present in RM and have been identified as the cause of several foodborne outbreaks. Methodology: The objective of this study was to assess the risk-benefit balance and quantify the health impact of RM consumption in terms of Disability-adjusted life years (DALY). The microbiological hazards Listeria monocytogenes, Salmonella spp., Campylobacter jejuni and Shiga toxin-producing Escherichia coli were considered next to potentially beneficial components such as vitamins A and B2. Mathematical modeling, including predictive modeling of bacterial inactivation and growth, were used to quantify the DALYs associated to the consumption of RM directly from vending machines. Published data were used to perform exposure assessment (initial concentration and prevalence of pathogens, growth models of pathogens in milk according to different storage conditions), hazard characterization (dose-response models) and risk characterization (estimating the number of cases due to milk consumption). BCoDE was used to estimate the associated DALYs. Dutch food composition database was used to estimate the vitamins A and B2 intake through milk consumption. Modelling resources and GBD Results Tool were used to establish the associated risk prevention and to estimate the associated DALYs, respectively. Results: Despite the evidence for health benefits is limited and that the included pathogens do not reach high levels under proper storage, in extreme conditions (3 days under 8°C), 7.6 DALYs/year were estimated to be lost due to listeriosis. Still, preventable DALYs/year associated to vitamins would not exceed 1. Conclusions and Relevance: Quantification into DALYs will aid the public debate on the possible benefits and risks regarding the growing popularity of the consumption of RM. The added value of such a quantitative assessment is that consumers can be informed on the magnitude of the risk and the expected health impact. Special efforts are needed to control storage and to ensure the safety of RM.Ricardo Assunção thanks EU-FORA – The European Food Risk Assessment Fellowship Programme funded by the European Food Safety Authority (EFSA).N/