Which action could cause cross-contamination in a self-service area?

Cross-contamination in a self-service area may happen when there is bacteria on a kitchen that transfers to the food through direct contact. Usually in the culinary arts, the most common kitchen tools that tend to be cross contaminated is a knife or a cutting board. In fact it is not just bacteria that gets carried or transferred from one place to another but it could also be a virus or toxin of some kind or even a cleaning product but whatever it is, if it happens to come contact with someone’s food this is considered a cause for a cross-contamination.