For many years, FDA has used product sampling and testing as one tool to better characterize microbial risk. Beginning in 2014, the agency began developing a new, more robust approach to sampling assignments to assess microbial contamination in food commodities.

Cyclospora oocysts
Oocysts of C. cayetanensis viewed under differential interference contrast (DIC) microscopy.
Image/CDC DPDx

Under this new approach, the FDA collects a statistically-valid number of samples of targeted foods over a shorter period of time (12-18 months) to help identify common factors among positive findings.The sampling design for each food takes into account the volume of the target food that is both imported and produced domestically, and the number of states/countries that produce the target food, to reflect what U.S. consumers are likely to find in the marketplace.

Commodities sampled to date under the new approach have included sprouts, whole fresh avocados, raw milk cheese, cucumbers, and hot peppers. For fiscal year 2018, the FDA has been sampling fresh herbs, specifically basil, parsley, and cilantro, along with processed avocado and guacamole, with samples coming from both domestic and imported sources.

Fresh cilantro, parsley and basil are typically eaten without having undergone a ‘kill step’ (such as cooking) to reduce or eliminate pathogens and are grown low to the ground, making them susceptible to contamination. The sampling assignment was developed to allow FDA to obtain baseline estimates of the prevalence of Salmonella and Shiga toxin-producing E. coli (STEC) in these herbs.

The agency added to this sampling assignment its recently developed and validated new analytical method to test for the parasite Cyclospora cayetanensisCyclospora has caused outbreaks in the U.S. linked to imported produce, including basil and cilantro. Although it’s unknown exactly how food and water become contaminated with Cyclospora, prior outbreaks have been associated with produce grown under insanitary conditions. This highlights the importance of strong sanitation and worker hygiene practices to prevent contamination, since rinsing or washing food is not likely to remove the parasite.

The results of this increased surveillance sampling so far this summer have been that two samples of cilantro offered for import from two producers in Mexico were positive for Cyclospora. In response to the finding, FDA refused entry for these shipments, and will take action to prevent contaminated cilantro from those firms from entering the U.S. As part of a broader effort under the FDA Produce Safety Partnership with Mexico, the two countries are working closely to investigate the cause of contamination.

Domestically, a cilantro sample collected at a distributor in July tested positive for Cyclospora. Following that finding, FDA initiated an investigation and another sample was collected on the farm that also tested positive for Cyclospora. In response, the FDA worked closely with state officials to voluntarily recall and embargo potentially affected product, and has been working with the farmer on corrective actions geared toward common routes of contamination.

Although this is the first confirmed evidence of the presence of Cyclospora in domestic produce, FDA is currently unaware of illnesses associated with the product, and trace forward efforts do not indicate there are any connections between this domestic finding of contaminated cilantro and multistate outbreaks of Cyclospora illnesses investigated this spring and summer.

The findings of Cyclospora in both domestic and imported produce highlight the importance of FDA’s surveillance activities to better define risks.