One type of chemical sanitizer used to wash leafy greens could increase the risk of E.coli 0157:H7 contamination when greens are irradiated.

According to a study published in the February 2014 issue of the journal Food Control, the use of chlorine-based sanitizers can reduce the ability of X-ray irradiation to kill E.coli 0157:H7.

In tests, another type of chemical sanitizer, peroxyacetic acid-based sanitizers (PAS), was found to make E. coli 0157: H7 more susceptible to irradiation.

“These results suggest that PAS may be preferred for irradiated baby spinach,” according to an abstract of the study, which was conducted by Michigan State scientists Scott Moosekiana, Sanghyup Jeong and Elliot Ryser.

Chemical sanitizers are widely used to minimize cross-contamination during commercial flume washing of leafy greens.