Which of the following is NOT one of the five common risk factors for foodborne illness?

Using outdated ingredients is indeed not one of the five common risk factors for foodborne illness. The focus of the five risk factors primarily revolves around practices that directly contribute to the spread of pathogens or contamination during food handling, preparation, and service.

The other factors emphasize critical areas such as sourcing, cooking temperatures, and hygiene practices. Purchasing food from unsafe sources can introduce harmful bacteria or toxins right at the beginning of the food handling process. Failing to cook food correctly relates to inadequate heat treatment that does not sufficiently kill pathogens present in food, leading to potential illness. Lastly, practicing poor personal hygiene, such as inadequate handwashing or improper handling of food by food handlers, can lead to the transfer of contaminants from individuals to food.

Thus, while outdated ingredients can pose risks, they are not categorized under the primary risk factors that are crucial to prevent foodborne illnesses in the same way the other factors are.