Biological Hazards


The biological hazard that has caused the most illnesses in peanuts and peanut products is Salmonella. Symptoms of Salmonellosis include nausea, vomiting, diarrhea, and fever. Illness can sometimes lead to hospitalization and even death.

The best way to keep consumers safe from illness is to reduce the risk that food becomes contaminated. Risk is reduced when the supply of ingredients and other raw materials is clean, workers use good personal hygiene and cross-contamination is prevented through effective sanitation practices. Much of this may be managed through GMPs discussed earlier.

It is not possible to eliminate the risk of Salmonella in raw peanuts, so processors must treat peanuts in ways that kill the organisms. Inactivation, killing, and elimination are all terms that refer to reducing pathogens to a level that is unlikely to cause illness. Cooking, or heat treatment, is most frequently used to destroy Salmonella in peanuts. For cooking to be effective, the peanuts must reach an adequate temperature for a long enough time to kill the microorganisms.

Perhaps the most overlooked risk of contamination of peanuts and peanut products is recontamination after cooking. Several illness outbreaks have been caused by post-process contamination. Preventive controls should be in place to prevent reintroduction of Salmonella after inactivation processes.

Other biological hazards of lesser importance for peanut processors include pathogenic E. coli, Bacillus cereus, Clostridium botulinum, Clostridium perfringens, Listeria monocytogenes and Staphylococcus aureus. These are of concern primarily when using other raw ingredients in peanut products (e.g., spices, dairy).


Viruses are common in the environment. They can be transmitted by people, contaminated food, and contaminated water and on environmental surfaces. Viruses do not grow in food but can persist in foods without growing because the need no food, water, or air to survive. Viruses cause illness by infecting living cells and reproduce inside the host. Virus contamination of peanuts or peanut products is rare. The risk of virus is more about workers getting exposed to infection, so good personal hygiene practices, keeping the environment clean and keeping ill workers out of the facility are some of the best measures.

Norovirus is the number one cause of foodborne illness. It causes nausea, vomiting, diarrhea, headache, and fever.


Foodborne parasites are reported much less frequently than viral or bacterial agents. They can be a problem in areas where sanitation systems are deficient. They may be transmitted through food or water that is contaminated by fecal material shed by infected hosts. Preventing contamination includes practicing good personal hygiene, avoiding insufficiently treated animal waste as crop fertilizer, handling sewage properly and treating water sufficiently.

Common foodborne parasites include:

  • Cryptosporidium parvum
  • Cyclospora cayetanensis
  • Giardia intestinalis
  • Toxoplasma gondi
  • Trichinella spp.