Whether a contaminated food such as tomatoes caused an outbreak of gastrointestinal disease is a simple example of:

The answer to this question is: Casual association
In biological term, casual association refers to The relationship between an assumption cause with the outcome that consistent with our current medical knowledge. In this case,it is already known that contaminated food contains toxic substances that could become a hindrance for our organ's functions

1. aspect is nothing really because the answer is right in front of your face