Health Risk Assessment Approach Research Articles

An example of an integrated approach for health and environmental risk assessment: the case of organotin compounds

Because environmental decision making based solely on simple compilation of toxicological data on either wildlife or humans in isolation can not give effective answers about the nature and levels of risk, an integrated approach for risk assessment of adverse effects of chemicals is required. Integration of available information on health and environmental effects, from in vitro to the level of humans, across various species, across different endpoints, and in combination with integrated exposure data, permits enhanced estimation of the potential risks posed by various agents. Mechanistic and quantitative consideration are the keys in this process. A framework for integrated risk assessment has been proposed by an international workgroup. The value and utility of the integrated approach is shown using the example of organotin compounds.

Incidence and control of Listeria monocytogenes in foods in Denmark

The Danish regulatory policy on Listeria monocytogenes in foods is based on the principles of HACCP and was developed using a health risk assessment approach. The Danish policy focuses examinations and criteria for L. monocytogenes in ready-to-eat foods and is based on a combination of inspection and product-testing. Based on current epidemiological information from several countries, a concentration of L. monocytogenes not exceeding 100 cfu/g of food at the time of consumption, seems to be of low risk to the consumers. In Denmark, ready-to-eat foods have been placed into six categories where absence of L. monocytogenes in 25 g is required in foods heat treated in the final package and in heat-treated as well as preserved, non heat-treated foods which can support growth within the shelf life. This level is necessary in foods capable of supporting growth, in order not to exceed 100 L. monocytogenes per g at the point of consumption. In heat-treated and preserved foods, which are not supportive of growth within the shelf-life and for raw, ready to eat foods, a level below 10 L. monocytogenes per g is regarded acceptable. A level between 10 and 100 L. monocytogenes per g is not satisfactory and a level above 100/g is not acceptable. Data on the qualitative and quantitative occurrence of L. monocytogenes in foods in Denmark are presented and discussed. In 1997 and 1998, greater than 15,000 samples from different categories of food were examined (semi-quantitatively) for the presence of L. monocytogenes. A significant difference could be seen in the number of samples containing more than 100 L. monocytogenes per g, between different categories of foods (1997, P=0.001; 1998, P=0.016). In 1997, preserved meat products and preserved fish products and to a lesser extent vegetables and meat or vegetable mayonnaise were more likely to contain high numbers (i.e. above 100 cfu/g) of L. monocytogenes than other food categories. In 1998, preserved meat products, but also heat-treated meat products, vegetables and meat or vegetable mayonnaise had the highest frequency of samples with >100 L. monocytogenes per g. In a survey performed in 1994 and 1995, 1.3% of ready-to-eat food samples (heat-treated meat products, preserved meat and fish products) were found to be contaminated with L. monocytogenes at a level above 100 cfu/g. The samples included in this survey were primarily products produced by authorized companies and were comprised mainly of vacuum packed products or products packed in modified atmosphere and with long shelf lives, typically above several weeks. The corresponding percentages of positive samples primarily processed in the retail outlets (heat-treated meat products, preserved meat and fish products) in 1997 and 1998 were 0.3% and 0.6%, respectively. The results suggest that ready-to-eat meat and fish products with extended shelf-lives produced by authorized companies are more likely to contain high numbers (>100 cfu/g) of L. monocytogenes than products processed in the retail sector which often have a shorter shelf life.

Factors contributing to discrepancies in population monitoring studies

A review of the scientific literature on population monitoring studies (on non-accidentally exposed populations) frequently show that many of these studies using similarly exposed populations and the same laboratory techniques do not produce consistent results. To illustrate the problem, a brief review of studies using well validated techniques (chromosome aberrations and hprt gene mutation) to elucidate genotoxic effects of cigarette smoking is presented. Although many factors can contribute to the generation of discrepant results, two obvious factors are small sample sizes and inadequate experimental data. In addition, a new factor on genetic susceptibility should be considered in population studies whenever appropriate. The new factor is based on recent data showing the influence of polymorphic metabolizing genes on response to environmental mutagens towards biological effects and disease outcome. The common ones include the cytochrome P450 and the glutathione S-transferase genes. The inclusion of susceptibility factors in population monitoring may revolutionize the approach for health risk assessment and for environmental regulations.

The Canadian position on Listeria monocytogenes in ready-to-eat foods

The Canadian regulatory policy on Listeria contaminated foods, based on the principles of HACCP, was developed using a health risk assessment approach. Our updated policy reflects current knowledge that the risk of contamination by L. monocytogenes can be reduced, but the organism cannot always be eradicated from finished product or the environment. The policy directs inspection and compliance action to ready-to-eat (RTE) foods which are capable of supporting growth of the organism. More specifically, the highest priority is given to those RTE foods which have been causally linked to listeriosis and those with a greater than 10 day shelf-life. The policy is based on a combination of inspection, environmental sampling and product testing.Foods have been placed into three categories, based upon health risk. Products in Category 1 have been causally linked to outbreaks of listeriosis and receive the highest priority in inspection and compliance activities. The presence of L. monocytogenes in these RTE foods will trigger a Class I recall with consideration of a public alert. Category 2 contains all other RTE foods which are capable of supporting growth of L. monocytogenes and have a shelf life exceeding 10 days. These products require a Class II recall with possible consideration of a public alert and receive the second highest priority in inspection and compliance activity. Category 3 contains two types of RTE food products; those supporting growth with a < 10 day shelf life and those not supporting growth. These products receive the lowest priority in terms of inspection and compliance action. For Category 3 RTE foods, factors such as the presence or absence of GMPs, levels of L. monocytogenes in the food (action level 100 cfu/g), and/or a health hazard evaluation are all considered in the compliance action taken.

Intermedia transfer factors for modeling the enviromental impact of air pollution from industrial sources

Toxic contaminants emitted to the atmosphere may be transformed and/or transported to other enviromental media such as water, soil, and biota. Many models have been developed to assess the impact of these emissions on human health and ecosystems. These models require input of chemical-specific parameters called intermedia transfer factors (ITFs). This study focuses on assessing the accuracy of ITFs used in modeling the enviromental impact of benzene, 2,3,7,8-TCDD and hexavalent chromium because these chemicals pose significant health risks and are widely emitted from various industrial processes. Many of the IFTs cited in the literature were estimated rather than measured which highlights the need for employing the most accurate estimation techniques available. This study can be used to refine the health risk assessment approach for identifying major enviromental hazards caused by industrial emissions and thus elucidating effective control strategies.