A new study suggests that some organic meats may be more likely to carry the toxoplasmosis parasite, which like E. coli and other pathogens, can be harmful if the meat is undercooked. The research was published online May 22 in the journal Clinical Infectious Diseases, reports MSNBC.
"The new trend in the production of free-range, organically raised meat could increase the risk of Toxoplasma gondii contamination of meat," the authors wrote.
The new research reviews the foods most likely to carry the parasite, and how people can prevent becoming sickened by it. The foods with the greatest chance of carrying toxoplasmosis parasites in the U.S. include raw ground beef or rare lamb; unpasteurized goat's milk; locally produced cured, dried or smoked meat; and raw oysters, clams or mussels.
Growing consumer demand for "free-range" and "organically raised" meats, especially pork and poultry, will probably increase the prevalence of T. gondii when people undercook and eat these foods, according to the study's authors, Dr. Jeffrey Jones, of the parasitic diseases branch of the Centers for Disease Control and Prevention, and J.P. Dubey, of the USDA's Animal Parasitic Disease Laboratory.
Free-range animals such as pigs or chickens are more likely to have access to contact with grass, soil water or feed that has been in contact with infected cat feces (a common carrier for toxoplasmosis), or to rodents or wildlife infected with T. gondii.
Compared with chickens raised indoors, the prevalence of the parasite in free-range chickens is much higher, anywhere from 17 percent up to 100 percent, in some estimates. (But the risk is low for chicken eggs, the authors noted.) Other research has shown that more organically raised pigs have tested positive for T. gondii than conventionally raised pigs.
Sheep also have a higher likelihood of being contaminated with toxoplasma, as do game meats such as deer, elk, moose and wild pig. Beef and dairy products have not yet played a main role in transmitting the infection, except for eating raw or undercooked ground beef.
To prevent getting sickened by toxoplasmosis, the researchers recommended cooking whole cuts of pork, lamb, veal or beef to 150 degrees Fahrenheit, and resting the meat for three minutes before eating it. Ground meat and wild game should be cooked to 160 F or higher, and poultry to 165 F. Microwave cooking may not kill the parasite.