Sausage making has never been pretty, but the art evolved as an excellent way to make parts of the meat useful that are not so easily eaten as simple cuts. One trick sausage makers use to achieve a safe, edible product relies on harmless bacteria that acidify the sausages as they ferment the meat mixture. The acidification kills off harmful pathogens, protecting consumers from food-borne illnesses.
At least that is the theory. Some people have been getting sick after eating fermented sausages -- products like pepperoni, salami, or chorizo; now researchers believe they have found an explanation for why foods that have been safe for generations may now be causing illness.
In an article published in mBio, researchers from the University of Copenhagen, Denmark, and the University College Cork, Ireland, found that antibiotics used in factory farming kill the good bacteria used to ferment sausages, while leaving harmful bacteria such as e. coli or salmonella alive. The low residual levels are too low to keep the bad bacteria down. But the failure of the good bacteria to thrive means that the mechanism for killing any harmful microorganisms cannot be relied upon. Even levels of antibiotic residuals that are legal under current US and European law may have this undesired side effect.
This leaves a strange paradox: one might think a bit of residual antibiotics would keep diseases down (not considering the evolution of superbugs, of course). But the reverse may be happening. Sausages with traces of antibiotics will be subject to further investigation in the wake of this finding, to ensure that current processes to ensure food safety can account for the possibility that an antibiotic sausage may be more dangerous.
More importantly, as the authors of the study note:
Our findings provide a possible explanation for outbreaks and disease cases associated with consumption of fermented sausages and offer yet another argument for limiting the use of antimicrobials in farm animals.