Researchers from the FDA have found that processed avocados and finished guacamole can be contaminated with Salmonella spp. and Listeria monocytogenes, according to a recent report.

“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,” according to the research report.

Although the report was just released in recent days, it covers a sample collection and testing program that ran from 2017-19. The project tested more than 800 samples, but had initially been scheduled to check 1,600 samples — 800 each from foreign and domestic companies — according to the Food and Drug Administration report.

The reduction in sampling size came in two waves. The first reduction came in July 2018 when the FDA adjusted its collection target to 1,200 samples — 936 domestic and 264 of international origin — after initial sampling confirmed that a relatively small number of firms, particularly domestic firms, produce and/or distribute processed avocado.

“In March 2019, the FDA further reduced its collection target to account for a 35-day lapse in federal appropriations that began on Dec. 22, 2018, and the associated impact on the workload of the agency field staff. Similar slight adjustments were made for the same reason to other food sampling assignments as well,” according to the FDA’s report.

Ultimately, the FDA collected and tested 887 processed avocado and guacamole samples — 571 domestic and 316 of international origin — from November 2017 to September 2019.

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 that has been proven to eliminate pathogenic microorganisms in food, and it is often used in the manufacture of processed avocado and guacamole. In seeking to exclude HPP-treated products, “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 action
The FDA detected Salmonella spp.in two samples that were from the same brand of domestically manufactured guacamole from different lots. Neither sample had received HPP treatment. 

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,” according to the report.

 The FDA also conducted one follow-up inspection of a domestic facility, and state officials in Florida conducted one domestic inspection. The FDA refused to admit certain foreign lots associated with positive test results and 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,” the report stated.

In addition to confirming that Salmonella spp. and Listeria monocytogenes may be present in processed avocado and/or guacamole, the sampling 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 FDA researchers reported. 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.

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