Quantitative Risk Assessment of Human Salmonellosis and Listeriosis Related to the Consumption of Raw Milk in Italy

Abstract

Two quantitative risk assessment (RA) models were developed to describe the risk of salmonellosis and listeriosis linked to consumption of raw milk sold in vending machines in Italy. Exposure assessment considered the official microbiological records monitoring raw milk samples from vending machines performed by the regional veterinary authorities from 2008 to 2011, microbial growth during storage, destruction experiments, consumption frequency of raw milk, serving size, and consumption preference. Two separate RA models were developed: one for the consumption of boiled milk and the other for the consumption of raw milk. The RA models predicted no human listeriosis cases per year either in the best or worst storage conditions and with or without boiling raw milk, whereas the annual estimated cases of salmonellosis depend on the dose-response relationships used in the model, the milk storage conditions, and consumer behavior in relation to boiling raw milk or not. For example, the estimated salmonellosis cases ranged from no expected cases, assuming that the entire population boiled milk before consumption, to a maximum of 980,128 cases, assuming that the entire population drank raw milk without boiling, in the worst milk storage conditions, and with the lowest dose-response model. The findings of this study clearly show how consumer behavior could affect the probability and number of salmonellosis cases and in general, the risk of illness. Hence, the proposed RA models emphasize yet again that boiling milk before drinking is a simple yet effective tool to protect consumers against the risk of illness inherent in the consumption of raw milk. The models may also offer risk managers a useful tool to identify or implement appropriate measures to control the risk of acquiring foodborne pathogens. Quantification of the risks associated with raw milk consumption is necessary from a public health perspective.

Paediatric HUS Cases Related to the Consumption of Raw Milk Sold by Vending Machines in Italy: Quantitative Risk Assessment Based on Escherichia coli O157 Official Controls over 7 years

“…No official estimates exist for the total number of raw milk consumers (Crotta et al., ), and, as observed in previous RAs (Giacometti et al., ,b), consumer habits, meanly different percentages of consumers not boiling milk before consumption, strongly influence the number of estimated cases. For this reason, RA should consider real‐life scenarios to avoid overestimating the total cases.…”

“…Due to the low modelled concentration of STEC O157:H7 in milk also in the worst scenario, the practice of boiling milk roughly reduces the risk of HUS to zero (Giacometti et al., , ,b). Based on this observation and to simplify the model, we assumed that in case of boiling milk before consumption the risk of HUS is fixed at zero.…”

“…This study undertook a national RA to estimate the HUS risk in paediatric population associated with the consumption of raw milk. The survey considered both the marketing/distribution of this commodity over a 7‐year period and assessed different scenarios known to influence previous RA results (Giacometti et al., ,b), such as consumer habits in terms of boiling milk and giving raw milk to children.…”

Raw and Heat-Treated Milk: From Public Health Risks to Nutritional Quality

“…Over the last ten years, QMRA models have been developed in Australia [40] and New Zealand [41], in the United States [42,43] and in Europe, specifically in Greece [44], Italy [45][46][47][48][49][50] and the United Kingdom [51], to evaluate the real risk associated with consumption of raw and/or pasteurized milk.…”

“…In details, the predicting models developed to estimate the risk of disease after consumption of raw drinking milk regarded the risk of campylobacteriosis [40,41,45,47], listeriosis [41,43,46], hemolytic uremic syndrome (HUS) [41,45,48], salmonellosis [41,46] and staphylococcal disease [42,50] (Table 3). …”