The weight of food and water contamination
The studies involved an examination of both the infectivity potential and the survival capability of C. parvum in beef, water and lettuce. Various stresses such as heating, freezing and chemical preservatives and their impact on the parasite were considered. The model was based on the distribution and incidence of C. parvum in the water and food supply as well as the reduction potential of oocysts any treatment could yield. Additionally, the amount of contaminated food or water consumed in relation to the percentage of the people exposed who become ill was assessed. Thus, after identifying and, characterising the hazard, assessing its exposure and qualifying the risks involved, some general conclusive evidence was gathered. One of the main findings for water is that regarding baseline conditions the risk posed in potable water is low. Contaminated water is that which usually comes from areas of unprotected water sources such as if there is livestock, animal waste or run-off water from agricultural land nearby. In the case of beef, the main risk came from contamination of the faeces. However, freezing, thawing and cooking was found to significantly reduce the properties of the parasite and thus also the risk.. With lettuce, initial contamination coming once again from animal manure as well as agricultural runoff caused by rainfall. Ways to reduce the risk of contamination in lettuce is to wash it, remove outer leaves and be aware of duration and temperature storage. Now that routine methods for the isolation, detection and typing of C. parvum in food and water have been developed, their application can extend to epidemiological as well as in inoculation studies. Furthermore practical strategies to control the pathogen in the food and water industry may be further developed.