Food-borne protozoa.

Pathogenic protozoa are commonly transmitted to food in developing countries, but food-borne outbreaks of infection are relatively rare in developed countries. The main protozoa of concern in developed countries are Toxoplasma, Cryptosporidium and Giardia, and these can be a problem in immunocompromised people. Other protozoa such as Entamoeba histolytica, Cyclospora cayetanensis and Sarcocystis can be a food-borne problem in non-industrialised countries. C. cayetanensis has emerged as a food-borne pathogen in foods imported into North America from South America. Microsporidia may be food-borne, although evidence for this is not yet available. The measures needed to prevent food-borne protozoa causing disease require clear assessments of the risks of contamination and the effectiveness of processes to inactivate them. The globalisation of food production can allow new routes of transmission, and advances in diagnostic detection methods and surveillance systems have extended the range of protozoa that may be linked to food.