What is the primary cause of Salmonella contamination?

Salmonella contamination primarily occurs through various food sources, and the correct option reflects that multiple types of food can be involved in these outbreaks. Raw poultry and eggs are particularly notorious for being carriers of Salmonella, as these foods can harbor the bacteria even before cooking. This means that improper handling or cooking of these items can lead to infection.

Untreated milk and dairy products also pose a significant risk. If milk is not pasteurized, it can contain Salmonella bacteria, which may not be killed during consumption if the product is consumed raw.

Raw vegetables can sometimes carry Salmonella due to contamination during handling or processing, but it's more commonly associated with animal products. Nonetheless, the comprehensive statement that all these food sources can contribute to Salmonella contamination is crucial in understanding food safety.

Thus, the choice indicating that all of the food types listed can be primary causes of Salmonella contamination encompasses the full range of risks and emphasizes the importance of safe food practices across various categories of food.