Which of the following practices can lead to foodborne illness?

Not storing ready-to-eat food above raw food can indeed lead to foodborne illness due to the potential for cross-contamination. When raw food, such as raw meat, poultry, or seafood, is stored above ready-to-eat foods, any juices or contaminants from the raw food can drip down onto the ready-to-eat items. This creates a risk of bacteria from the raw food coming into contact with food that is meant to be consumed without further cooking, which can lead to illnesses if those bacteria are ingested.

In food safety, it is crucial to maintain proper food storage practices to prevent these types of risks, ensuring that foods are not only stored correctly but that ready-to-eat items are kept separate from raw items to protect against contamination. Other practices mentioned in the choices focus on hygiene and safe food handling, which are important but do not directly illustrate the specific risk of cross-contamination that occurs when food isn't stored correctly.