Food parasites to watch out for: Top 10

Last year’s outbreak of the foodborne pathogen Cyclospora in pre-made salad mixes brought a sometimes-overlooked type of pathogen into the forefront of people’s minds once again: parasites.

Some of the most well-known culprits behind food recalls are bacteria that live or die based on environmental conditions, like Salmonella, Listeria and E. coli. While parasites and bacteria might be present in environments that aren’t closely monitored for threats, parasites are organisms that live on or in another living host, gaining sustenance at the expense of said host. Cyclospora is a single-cell parasite that, like most other foodborne parasites, cause food poisoning symptoms like diarrhea, fatigue and cramps.

The World Health Organization and the Food and Agriculture Organization of the United Nations have zeroed in on the top foodborne parasites around the world. They based their list on the sheer volume of illnesses caused, global distribution, morbidity, mortality, trade relevance and socio-economic impact, among other factors.

The top 10 are:

1. Taenia solium — most prevalent in the Southern Hemisphere and predominant in humans and pigs.
2. Echinococcus granulosus — a tropical parasite mostly transmitted to humans by dogs, either by direct contact or by the consumption of food or water contaminated with dog feces.
3. Echinococcus multilocularis — a Northern Hemisphere parasite that can cause cysts, itching and chest pain (just like its cousin, which is number two on this list).
4. Toxoplasma gondii — can be found anywhere in the world; usually transmitted through raw meat.
5. Cryptosporidium — mostly associated with water; is also known as “Crypto.”
6. Entamoeba histolytica — infection is known as amebiasis; spreads through fecal contamination of water or food.
7. Trichinella spialis — Prevalent mostly in Mexico, but also found in southern Asia, Africa, South America and the Middle East; has a broad host range.
8. Opisthorchiidae — A family that includes a few parasites that are commonly transmitted through freshwater fish; potentially carcinogenic.
9. Ascaris spp. — parasitic worms often found in soil, transmitted by ingestion of its eggs.
10. Trypanosoma cruzi — causes Chagas disease, which can be chronic; only found in the Americas.

The study goes into great detail on the symptoms a person would experience, it is worth a read through for any food safety professional in today’s global food chain. Cyclospora comes in at number 13 on the source list, so we did not cover it above. Other well-known parasites that affect the food system are Giardia duodenalis and Taenia saginata.

As many of these parasites are waterborne, water testing is key for their detection, as it is with certain bacterial pathogens. And, as always, key food safety practices — such as sanitizing surfaces thoroughly, washing produce and washing hands — are critical in the kitchen (both commercial and residential) to prevent their spread.