The answer could be almost nobody or almost everyone, depending on how the question is asked. In another FMI question, people are asked what foods they avoid buying because they feel the foods may be unsafe. Although red meat is most frequently mentioned as a food to be avoided because of safety concerns, milk is not listed as one of the foods to avoid for safety reasons. Thus, looking at these responses, we could say that people are not concerned about drug residues, at least in milk. The answer is almost everyone could become concerned, depending on the circumstances.
Consumers have a fragile confidence in the safety of the foods.
A primary reason for the fragility of confidence in safety of foods is that consumers don't trust regulatory agencies. Most urban consumers also do not know enough about agriculture to trust that farmers and ranchers will look out for the consumer interest. Because of their lack of trust in government or agriculture to protect safety of foods, consumers can be easily swayed by media reports about the dangers of any product. Food residues are perceived as being risky because people don't feel they have any control over their exposure to these products. Risks that seem fair are more acceptable than those that seem unfair.