The risk assessments are done by experts at Health Canada. The agency follows the risk assessments that are done. They are always done in relation to the risks that the pathogen poses. How did it end up in the food? Does the product need to be cooked or not? How much does it contain? All of these factors are part of Health Canada's risk assessment. Health Canada then determines whether a risk exists or not. Finally, the agency issues a recall. That is the normal procedure that has always been followed. Health Canada assesses every product that may fall into a grey area.
On March 17th, 2010. See this statement in context.