A study conducted by the epidemiologists at the University of Iowa, College of Public Health analysed 395 separate pork packages concluded that there was no difference in the prevalence of Staphylococcus aureus in pork from either background, be it conventionally farm raised animals or those labeled antibiotic –free.
The samples were taken from 36 stores across three states: Iowa, Minnesota, and New Jersey.
Of these, 230 were found to carry the Staphylococcus aureus, and of these 6 % carried the methicillen-resistant S. aureus (MRSA).
This suggests that there is no difference between S. aureus prevalence between conventionally raised pork (202 cases out of 300) and alternative, antibiotic-free pork (54 cases out of 95), though the caveat must be borne in mind that the ‘antibiotic-free’ label is not a third-party assessment.
The study underscores the need for understanding how drug resistance is transmitted. After all, other European studies show the tenable link between MRSA and antibiotic use, ie that absence of antibiotic use relates to low MRSA presence.
The present study does agree with findings on prevalence reported for Canada, and is similar (though of a greater magnitude) to other USA studies.
The study was published in PloS 1: O’Brian et al 2012: MRSA in Conventional and Alternative Retail Pork Products. PLoS ONE 7(1)