FDA recommends strict ozone validation



ROCKVILLE, Md.—Ozone treatments to reduce harmful pathogens during food processing and handling may be a good thing, but until proven, the Food and Drug Administration ( is recommending that apple juice and cider processors establish their own documented validation study—or choose another treatment method.

With the fall months ushering in increased interest in apple products, the FDA's guidance is targeting juice and cider producers in the wake of an outbreak of cryptosporidiosis found in apple cider in Ohio last fall that sickened 148 people. The illness' key symptom is severe diarrhea, caused by the protozoan parasite Cryptosporidium parvum.

Ironically, the affected cider was traced to a local orchard that had reportedly treated the juice with ozone. While the FDA acknowledges that ozone treatments can be effective in reducing levels of such harmful pathogens as E.coli, and is approved as a food additive that may be safely used as an antimicrobial agent, the agency says the approval "does not establish the effectiveness of ozone as an antimicrobial under particular conditions of use."

The FDA's message seems clear to at least one state agriculturist. "Cider makers who choose ozone treatment must either do their own validating studies, or run the risk of non-compliance with the [HACCP—Hazard Analysis and Critical Control Point] regulation, and the liabilities that might result from an incident of foodborne illness," says Richard Uncles, bureau of markets supervisor for the New Hampshire Department of Agriculture, Markets and Food.

Ozonization, as part of a water treatment, has been used by some produce growers and processors because, when incorporated correctly, it has been found to be safer and more effective than other treatments. In some cases, ozonization has also been found to be effective in attacking fungi that can kill produce or reduce its shelf life.

But because of variables in the ozonization process, the FDA is urging juice and cider processors to include an ozone validation method that will clearly document, at a minimum, a 5-log reduction of the most resistant organism likely to occur in the juice. (Each log is a reduction of 90 percent, so a 5-log reduction means that juice and cider processors must use treatment steps to ensure that 99.999 percent of a pathogen is destroyed.)

Variables of the ozone process that are worthy of validation, says the FDA, include:

  • Total concentration of ozone introduced into the juice;
  • Flow rate of ozone into the batch tank;
  • Treatment time;
  • Appropriate batch volume;
  • Degree of agitation needed to ensure that the ozone is uniformly dispersed in the juice.

In making its recommendations, the FDA argues that "compositional factors, such as the amount and type of juice solids present (e.g., sucrose and organic matter) can vary among different apple juice and cider products, and may affect the efficacy of a process."

A scientific validation study is needed to establish how these factors need to be controlled to ensure the "efficacy of the ozonization process," says the FDA, acknowledging that it is unaware of any published scientific study that establishes conditions for ozonization of apple juice or cider to achieve 99.999 percent pathogen reduction.

"The clear inference I get from the document," says Uncles, "is that since ozonization for apple cider has not been the subject of validation studies (to FDA's knowledge), and since validation is a requirement of a HACCP plan's 5-log pathogen reduction requirement, the FDA is not supporting the use of ozone at this time."

New Hampshire has approximately 65 apple cider producers, but Uncles indicates that most are staying with less expensive or otherwise proven contamination-control methods. After talking with one producer about ozonization, Uncles says, "their conclusion was that ozone was not an option at this point, owing to the tone of the FDA recommendations."

While it may be that the FDA's guidance impacts mostly larger apple juice/cider producers, Uncles says most of New Hampshire's producers "are resigned to a retail-only mode until such time as cost-effective methods of pathogen reduction, such as ozone, are proved efficacious. Hopefully, validation studies will be conducted to demonstrate the effective use of ozone."