# Food and Drinking Water as Sources of Pathogenic Protozoans: An Update
## 6 _Toxoplasma gondii_
### Distribution of T. gondii in Food Producing Animals and Derived Products  
In a molecular epidemiological study carried out in Belgium, _T. gondii_ could be isolated and detected by magnetic capture-qPCR in 14 out of 92 pig hearts collected in the years 2016 and 2017 from pigs raised on organic farms [156]. Mouse bioassay demonstrated the viability of _T. gondii_ in nine of the positive animals. Isolate genotyping by multiplex PCR on microsatellite markers showed that pig isolates belonged to type II, which is predominant in Europe [159]. Genotypes were highly related to those of human isolates, leading to hypothesize either transmission of _T. gondii_ from pigs to humans or infection of both species via a common source. In Northwestern Italy, genotype I was the most prevalent in different animal species; in Denmark, more than one-third of the isolates were attributed to genotypes Africa 1, HG12-like, and other atypical genotypes; in Portugal, 12.5% and 20.8% of isolates were identified as type I and mix/recombinant, respectively; and in Poland, the circulation in humans of type III strains associated with wildlife was was reported [156].  
Pork and lamb are major sources of _T. gondii_ infection, but tissue cysts can also be present in poultry, rabbits, cattle, and horses. Regarding swine farming, conventional finisher herds may be classified as low-risk, organic finisher herds as medium-risk, and sow herds, both conventional and organic, as high-risk. Recently, the global _T. gondii_ seroprevalence in pigs was reported to be 19%, with the lowest in Europe (13%) and the highest in Africa and North America (25%). The seroprevalence in Asian and South American regions were 21% and 23%, respectively. Processed pork products pose a lower infection risk than fresh raw pork because salting, freezing at \(-12\)\({}^{\circ}\)C, hot smoking, long fermentation, heating above 67 \({}^{\circ}\)C, irradiation, and high hydrostatic pressure can reduce or inactivate _T. gondii_ cysts in meat. Several studies confirmed the safety of ready-to-eat pork prepared using typical NaCl concentrations of 13% or higher, and industry fermentation and drying standard procedures [158].  
Data on prevalence in sheep flocks are available for the Emilia Romagna region, Italy, where a high prevalence of toxoplasmosis of 41.9% was reported. A seroprevalence of 18.7% was reported in goats for which _T. gondii_ represents a primary cause of abortion [165]. In farmed and free-ranging wild boars, seroprevalence were reported at 32% in North America; 26% in Europe; 13% in Asia; 5% in South America; 24.6% on Sardinia, Italy; 18.9% in southern Italy; and 15.5% in northern Italy [158; 165; 175].  
In the Emilia-Romagna region, Italy, a prevalence of 14% among wild water birds and a seroprevalence of 25% in roe deer were reported. The significance of toxoplasmosis in these animal species is of direct concern for public health since some are used to produce raw gastronomic preparations [165]. In southern Italy, the prevalence of _T. gondii_ determined by qPCR was 28.6% in wolves, 27.3% in badgers, 23.9% in foxes, and 14.3% in roe deer [162]. Moreover, the parasite was also detected in 6 out of 11 blue crabs from the Lesina Lagoon. Among 55 tissue samples, 12.7% were positive for _T. gondii_, with hemolymph and gills showing higher infection levels [176].  
Raw milk can pose a risk of infection due to tachyozoites of _T. gondii_ that can be shed in the milk of naturally infected animals. In Turkey, _T. gondii_ DNA was detected in 8% ewes and 4% goat raw milk samples but not in cheese samples [177]. In addition, according to a study from Iran, chicken, duck, and quail eggs can be contaminated by _T. gondii_ and pose an infection risk if consumed undercooked [178].