This blog has previously considered the relationship between antibiotic resistant bacteria and factory farming. Recently, I learned about another way in which industrial meat production is breeding microbes that kill humans all the more efficiently. This one has to do with the acidity of our stomachs, one of the ways in which our bodies protect themselves from microorganisms living in the food we eat.
A cow living on a diet of grass has a rumen with a neutral pH. The rumen is the ‘first stomach’ of grass eating animals. Inside, bacteria help to ferment undigestible grass into material the cow’s body can process. Along with these digestive bacteria, many other kinds are present. One sort – Escherichia coli – kills humans by releasing toxins that destroy the kidneys. ‘Normal’ E. Coli, of the sort found in cows since the 1980s, cannot tolerate an acidic environment. As such, our stomachs are pretty good at killing it and thus keeping it from killing us.
A cow in a factory farm does not eat grass. The corn it eats creates an acidic environment in the rumen. This makes the cows ill, while also helping to breed E. Coli that can survive passage through acidic human stomachs. Now, about 40% of feedlot cows have E. Coli in their rumens. Feeding them grass or hay for a few days before slaughtering reduces the number of E. Coli in the animal’s digestive tract by about 80%, but factory farms do not do this. Instead, they try to prevent E. Coli outbreaks through irradiation.
Just another way in which industrial meat farming perverts nature and threatens human health.
[Update: 22 January 2010] Apparently, new research has called this hypothesis about diet and e. coli into question: “different set of findings emerged to indicate that this particular strain did not, in fact, behave like other strains of E. coli found in cattle guts. Most importantly (in terms of consumer safety), scientists showed in a half-dozen studies that grass-fed cows do become colonized with E. coli O157:H7 at rates nearly the same as grain-fed cattle. An Australian study actually found a higher prevalence of O157:H7 in the feces of grass-fed rather than grain-fed cows. The effect postulated (and widely publicized) in the 1998 Science reportâ€”that grain-fed, acidic intestines induced the colonization of acid-resistant E. coliâ€”did not apply to the very strain of bacteria that was triggering all the recalls.”