It is a mystery, for the bacteria shouldn’t be able to gain resistance without exposure to the antibiotic. Scientists suggest some form of cross-contamination between the slaughterhouse and their testing, but only humans, cats and dogs receive fluoroquinolone antibiotics in Australia.
Consumer Reports sent shoppers to 136 stores in 23 states, belonging to the 13 largest supermarket chains, to see what kind of meat and poultry products raised without antibiotics are offered and at what price.
What they found is encouraging. The shoppers found that one chain, Whole Foods, is already offering nothing but meat and poultry raised without antibiotics. Several others – Giant, Hannaford, Shaw’s, Stop & Shop, Publix, and Trader Joe’s – had broad selections of these products. At only four chains were shoppers unable to find any organic or other products raised without antibiotics: Sam’s Club, Food 4 Less, Food Lion, and Save-A-Lot. [Source]
They also found that the antibiotic-free meats weren’t necessarily any more expensive. Unfortunately, this consumer preference has not made any inroads into processed meats – where 80% of U.S. meat ends up.
In a national survey, more than 85% of adult consumers said they thought that fresh meat raised without antibiotics should be available in their local stores and supermarkets. Consequently Consumer Reports have launched a new campaign – Meat Without Drugs, Stop the Superbugs with a companion website, www.MeatWithoutDrugs.org, and this video:
Scientists had expected that, on farms where the practice of giving antibiotics to livestock has ceased, germ immunity would slowly fade away. Alas, that is not the case:
To the team’s surprise, the entire bug community kept most of its armor against the antibiotics, even after 2 ½ years. When the researchers grew the bacteria in the lab, for example, 70% to 100% of them were still resistant to chlortetracycline when the pigs were slaughtered. “I didn’t expect such high levels of resistance would remain,” says Chénier, whose team will publish the results in the January issue of Microbial Ecology.
It might be due to resistance genes being attached to other genes that remain useful. Or it could be due to reinfection from fertiliser:
The new data, he says, suggest that the common practice of using swine waste as a fertilizer is like spreading truckloads of antibiotic resistance on farmland. Those bacteria can share their resistance with other bacteria that happen to be on crops and in downstream aquatic ecosystems—bacteria that could cause illness, Chénier says. “This is a time bomb.