Listeria monocytogenes is a foodborne pathogen that can cause listeriosis, a rare but severe disease whose invasive form has an estimated fatality rate of 20–30% of those who become ill. Typically, listeriosis occurs in individuals who have one or more underlying conditions that depress immune function, which makes them susceptible to the illness. Risk management strategies are required throughout the food chain to reduce the incidence of foodborne listeriosis. Public health objectives can be established to ensure continuous improvement in the health of the population with respect to a particular hazard and ideally should be based on an assessment of the risk to the population by the hazard. Food safety systems can be based on meeting a specific public health objective, to reduce the burden of foodborne disease. The International Commission on Microbiological Specifications for Foods has proposed the establishment of Food Safety Objectives (FSO) to provide a link between a public health objective and performance objectives and performance criteria that are established to control a foodborne hazard. An FSO can be used as a risk management tool for L. monocytogenes in ready-to-eat foods as the FSO establishes the stringency of the measures being used to control the hazard by specifying the frequency and/or cell number of L. monocytogenes in the food that should not be exceeded at the time of consumption. To establish an FSO based on a public health objective, the level of exposure that meets the public health objective must be determined. This requires an understanding of the risk characterization curve and the dose–response relationship for both the normal and the susceptible populations. This may be difficult, as there is considerable variation in the degree of susceptibility of individuals to L. monocytogenes, depending on their age, whether or not they are pregnant, and the severity of any underlying illness. It is likely that when establishing an FSO for L. monocytogenes both the normal and susceptible subpopulations will have to be considered. If the FSO is being met, there should be a concomitant reduction in illness as long as the main factors influencing the risk at the population level remain within the boundaries of the risk assessment. A reduction in illness can be measured through disease surveillance. Once a public health goal is achieved, new, technologically feasible goals should be considered to foster continuous improvement in reductions of listeriosis. Implementing effective food safety control measures, which ensure that the FSO is being met consistently, is key to reducing foodborne listeriosis.
Walls, I and Buchanan R. "Use of food safety objectives as a tool for reducing foodborne listeriosis." Food Control, 16, 2005, pages 295 - 799.