The U.S. Food and Drug Administration collected and tested processed avocado, the main ingredient in guacamole, and finished guacamole as part of the agency’s proactive and preventive approach to deploying its sampling resources with the ultimate goal of preventing contaminated food from reaching consumers.
The assignment began in November 2017 and ended in September 2019. In total, the FDA collected and tested 887 samples of processed avocado and guacamole (domestic and imported product) for Salmonella spp. and Listeria monocytogenes. This total is smaller than the initial number of samples the agency set out to collect and test because the agency encountered factors that twice required a reduction of the collection target, as explained in the Sample Collection section of this report (page 6).
As to the design of the assignment, the FDA directed its field staff not to collect products that had undergone high-pressure processing (HPP) or products intended for HPP. HPP is a “kill step” validated to eliminate pathogenic microorganisms in food, and it is often used in the manufacture of processed avocado and guacamole. In seeking to exclude from the assignment products that had been HPP-treated, the FDA’s intent was to focus on products that posed the greatest risk to consumers.
The agency learned during its evaluation of the test results that some of the products collected had received HPP treatment but were not labeled as such. FDA staff worked retrospectively with industry to identify the HPP-treatment status of the samples collected but could not determine the status of a number of samples. Those samples were designated as “could not ascertain” for purposes of the data analysis.
Findings and Follow-up Actions
The FDA detected Salmonella spp.in two samples which were later determined to be distinct samples of the same brand of domestically manufactured guacamole from different lots. Neither sample had received HPP treatment. In addition, the agency detected Listeria monocytogenes in 15 samples from nine different firms. Of those 15 samples, eight had not been HPP treated. The HPP-treatment status of the other seven samples could not be ascertained.
When the FDA detected a pathogen in a domestic sample, agency personnel worked with the company that owned or distributed the affected product to conduct a voluntary recall in all cases in which product was available, or likely to still be available, to consumers. The FDA also conducted one follow-up inspection of a domestic facility, and state officials in Florida likewise conducted one domestic inspection. As to the imported samples, the agency refused to admit lots associated with the positives and placed the responsible companies on import alert. In all, the agency placed two firms on import alert. In addition, the agency conducted whole genome sequencing (WGS) analysis on the positives but was unable to determine whether processed avocado or guacamole were the food vehicle associated with any known human illnesses.
In addition to affirming that Salmonella spp. and Listeria monocytogenes may be present in processed avocado and/or guacamole, the assignment data show that the estimated prevalence of these pathogens in the non-HPP-treated samples was higher than in the HPP-treated samples. This finding appears to support other research that shows HPP is effective at neutralizing pathogenic microorganisms, even as this assignment was not designed to compare possible differences based on HPP-treatment status. The findings also underscore the need for processors and others in the processed avocado and guacamole supply chain to comply with the FDA’s Preventive Controls for Human Food Rule and for importers of these foods to comply with the FDA’s Foreign Supplier Verification Programs Rule.
 Huang, H.; Wu, S.; Lu, J.; Shyu, Y.; and Wang, C. (2017). Current status and future trends of high-pressure processing in food industry. Food Control, Vol. 72, Part A, Feb. 2017, p. 1-8.
 The Preventive Controls for Human Food Rule requires food facilities to have a food safety plan in place that includes an analysis of hazards and risk-based preventive controls to minimize or prevent the identified hazards.
 The Foreign Supplier Verification Programs Rule requires that importers perform certain risk-based activities to verify that food imported into the U.S. has been produced in a manner that meets applicable U.S. safety standards.