On the heels of the Marler Clark retail chicken study, researchers from Wayne State University will publish an article in the June edition of Emerging Infectious Disease on contamination of retail meat.  In this study, investigators sampled retail meat in and around Detroit:

We collected 289 raw meat samples (156 beef, 76 chicken, and 57 turkey) from 30 grocery stores in Detroit, Michigan, USA, during August 2009–January 2010. Sixty-five (22.5%) samples yielded S. aureus: 32 beef (20.5%), 19 chicken (25.0%), and 14 turkey (24.6%) samples. Six samples, consisting of 2 beef (1.3%), 3 chickens (3.9%), and 1 turkey (1.7%), were positive for MRSA as evidenced by the presence of mecA.

The overall lower prevalence of S. aureus and MRSA than found in a previous study in the United States (40% and 5%, respectively) (1) might be explained by our exclusion of pork because pork and swine production have been major reservoirs of MRSA (4,7). However, different geographic location and cold sampling seasons in this study also might have caused the variations. The only multidrug-resistant MRSA isolate in this study (MRSA1) was from beef.

See retail meat.pdf.  By comparison, in the Marler Clark retail chicken study:

IEH Labs found S. aurea, or staph, in 42 percent of the samples overall and Campylobacter in 65 percent. The supermarket chicken was contaminated with other pathogens as well: 19 percent of the samples tested positive for Salmonella, one tested positive for Listeria, and 10 percent showed the presence of the methicillin-resistant S. aureus (MRSA). In an unusual finding, one of the chicken samples tested positive for E. coli 026, Shiga-toxin producing E. coli (STEC) bacteria more likely to be a contaminant of beef than poultry. Organic Chicken proved to be slightly less contaminated than nonorganic with 7 of the 13 (54%) testing positive for harmful bacteria.