FDA CDER wants to know if antimicrobial soaps are effective: Schaffner responds

Friend of the barfblog.com Don Schaffner of Rutgers University writes in this guest post:

The FDA might not be sure if antimicrobial soaps do anything, but I am. My colleague R. Montville[1] and I published a meta-analysis on the topic in 2011. As we noted in our manuscript, although differences in efficacy between antimicrobial and nonantimicrobial soap were small (∼0.5-log CFU reduction difference), antimicrobial soap produced consistently statistically significantly greater reductions when compared to plain soap. This difference was true for any of the antimicrobial compounds investigated (chlorhexidine gluconate, iodophor, triclosan, or povidone) where we had more than 20 observations to analyze.24673_1363044526205_4550195_n

But the story doesn’t end there. The American Cleaning Institute who funded[2] the meta-analysis study wanted to dig a bit further. A second article has been accepted for publication in the Journal of Food Protection, and is in the galley proof stage. That article, entitled “Quantitative Microbial Risk Assessment of Antibacterial Hand Hygiene Products on Risk of Shigellosis” used previously unpublished laboratory data, together with simulation techniques, to compare the ability of nonantibacterial and antibacterial products to reduce shigellosis risk. Our simulation assumed 1 million Shigella bacteria on the hands of a food handler who washed their hands and then handled melon balls, which were then eaten. When a plain soap hand treatment was simulated, we predicted that 50 to 60 cases of shigellosis would result (of 100 exposed). Conversely, each of the antibacterial treatments (0.46% triclosan, 4% chlorhexidine gluconate, or 62% ethyl alcohol) was predicted to result in an appreciable number of simulations for which the number of illness cases would be 0, with the most common number of illness cases being 5 (of 100 exposed). These effects maintained statistical significance down to as low as 100 Shigella per hand, with some evidence to support lower levels. Like I said, I think anti-microbial soaps work. If you think they don’t, show me the data.

[1]: No, not that Montville, his daughter.
[2]: Does that make me an industry shill? Please. Like anyone can tell me what to say.