Salmonella usually found in poultry

Washington: Salmonella is more frequently associated with poultry, which carry the bacteria. But agricultural produce is increasingly a vehicle for salmonella infection as well.

Scientists and public health experts don't completely understand how pathogens contaminate agricultural produce.

The bacteria can be found in animal faeces, which can spread through contaminated water, manure or improper handling.

It can enter tomatoes through the roots or flowers, or through cracks in the skin of the fruit or the stem scar. Once inside, the microbe is hard to kill without cooking.

Tomatoes have been linked to 13 outbreaks of salmonella infection since 1990, according to the Centre for Science in the Public Interest, a Washington advocacy group.