Cryptosporidium are single-celled parasites that cause a diarrheal disease called cryptosporidiosis.

These parasites can be found in:

  • soil
  • food
  • water
  • surfaces that have been contaminated with feces from infected humans or animals

The parasites require a human or animal (such as deer, cattle, birds, rodents) host in order to reproduce.

During reproduction, Cryptosporidium forms infectious oocysts with tough protective coatings that allow it to survive in water and other environments. This also allows it to survive for weeks or even months outside of a human or animal host. However, oocysts will die if exposed to dry conditions.

Symptoms of Cryptosporidium infection

The most common symptom of cryptosporidiosis is watery diarrhea.

Other symptoms can include:

  • abdominal cramps
  • nausea
  • vomiting
  • dehydration
  • weight loss

The onset of cryptosporidiosis is generally between two and 10 days after becoming infected with the parasite. Illness can last anywhere from a few days to four or more weeks. It may last longer in severe cases.

Healthy individuals who become infected may not show symptoms or may experience gastrointestinal illness. Symptoms are usually self-limiting in healthy individuals. For individuals with weakened immune systems, diarrhea and dehydration may be more severe and possibly life-threatening. Individuals may continue to excrete oocysts weeks after symptoms have subsided.

Cryptosporidum contamination on fresh fruits and vegetables

Cryptosporidium are widespread in the environment. The parasite is commonly found in surface waters such as:

  • ponds
  • streams
  • rivers
  • lakes

It is also found in:

  • mammals
  • birds
  • reptiles
  • amphibians

The detection of Cryptosporidium on fresh produce indicates that, at some point, the produce has come into contact with fecal matter.

Transmission onto fresh produce may occur through:

  • contaminated water that is used for irrigation or the application of agricultural chemicals
  • flood water that contacts the produce
  • contaminated dump tank or flume water used for postharvest washing of the produce
  • infected workers
  • run-off from improperly composted manure
  • wild animals passing through or grazing in production fields
  • flies that spread oocysts

Reducing the risk of Cryptosporidium contamination

A food safety management system consisting of Good Agricultural Practices (GAPs) can help minimize the risk of contamination.

This risk can be minimized by implementing preventative practices that include:

  • checking water quality (production and postharvest)
  • employee training on proper hygiene practices and handwashing
  • management of biological soil amendments (such as manure and compost)
  • separation of livestock and manure from produce production
  • field sanitation of equipment and containers
  • on-farm pest control

Cryptosporidium oocysts are not killed by sanitizer (such as chlorine bleach) at levels typically used for post-harvest rinsing of produce. The physical action of washing may remove some oocysts but will not eliminate them from produce surfaces entirely.

Contact us

Please contact the Inspection Programs Unit by email at fpo.omafra@ontario.ca or call 1-877-424-1300 for more information.