Austin, Tex.

IS free-range pork better and safer to eat than conventional pork? Many consumers think so. The well-publicized horrors of intensive pig farming have fostered the widespread assumption that, as one purveyor of free-range meats put it, “the health benefits are indisputable.” However, as yet another reminder that culinary wisdom is never conventional, scientists have found that free-range pork can be more likely than caged pork to carry dangerous bacteria and parasites. It’s not only pistachios and 50-pound tubs of peanut paste that have been infected with salmonella but also 500-pound pigs allowed to root and to roam pastures happily before butting heads with a bolt gun.

The study published in the journal Foodborne Pathogens and Disease that brought these findings to light last year sampled more than 600 pigs in North Carolina, Ohio and Wisconsin. The study, financed by the National Pork Board, discovered not only higher rates of salmonella in free-range pigs (54 percent versus 39 percent) but also greater levels of the pathogen toxoplasma (6.8 percent versus 1.1 percent) and, most alarming, two free-range pigs that carried the parasite trichina (as opposed to zero for confined pigs). For many years, the pork industry has been assuring cooks that a little pink in the pork is fine. Trichinosis, which can be deadly, was assumed to be history.

Agricultural scientists have long known that even meticulously managed free-range environments subject farm animals to a spectrum of infection. This study, though, brings us closer to a more concrete idea of why the free-range option can pose a heightened health threat to consumers. Just a little time outdoors increases pigs’ interaction with rats and other wildlife and even with domesticated cats, which can carry transmittable diseases, as well as contact with moist soil, where pathogens find an environment conducive to growth. The natural dangers that motivated farmers to bring animals into tightly controlled settings in the first place haven’t gone away.

This news is especially troubling for connoisseurs of fine pork. Pork lovers, supporters of sustainable meat and slow-food advocates have long praised the superior taste of the free-range option. According to the Web site of Legacy Manor, a Maryland farm that raises free-range pigs, it is “the way food used to taste.” Given such superlative enthusiasm, it’s worth wondering how this latest development will play out among the culinary tastemakers.