Health and food-safety experts have raised concerns about the practice of boiling eggs directly in the same pot as rice, warning that contaminated eggshells can introduce harmful bacteria into the cooking environment.

The concern is linked mainly to cross-contamination. Shell eggs can carry bacteria, including Salmonella, on their outer surfaces, while raw eggs can also spread germs to other foods, utensils and kitchen surfaces when they are handled improperly.

A report on the practice in Nigeria cited food-safety experts who recommended cooking eggs separately from rice as a precaution against possible contamination.

An academic study cited in the report found detectable E. coli and Salmonella in rice cooked with unwashed eggs in their shells, while the organisms were not detected in rice cooked with properly washed eggs. The findings suggest that the concern is primarily related to hygiene and cross-contamination rather than the eggshell itself being poisonous.

The United States Department of Agriculture advises consumers to wash their hands, utensils and work surfaces after handling eggs and to prevent raw eggs from coming into contact with other foods. It also recommends cooking eggs until both the white and yolk are firm.

Food-safety guidance generally follows four basic principles: clean, separate, cook and chill. Keeping raw or potentially contaminated foods separate from ready-to-eat foods reduces the risk of transferring harmful microorganisms.

Rice also requires careful handling after cooking. Bacillus cereus, a bacterium associated with rice and other starchy foods, can cause foodborne illness when cooked food is improperly cooled or stored for prolonged periods at unsafe temperatures. Some spores can survive cooking and later multiply if the food is handled or stored incorrectly.

For households that regularly boil eggs while cooking rice, using separate pots provides a straightforward way to eliminate the possibility of eggshell contamination entering the rice. Proper handwashing and cleaning of utensils and cooking surfaces are also important.

However, the practice should not be described as automatically causing food poisoning. The actual risk depends on factors including the cleanliness and condition of the eggs, handling practices, cooking temperatures and subsequent storage of the rice.