Washington—A new report from USDA’s Economic Research Service (ERS) uses import refusal data from the US Food and Drug Administration (FDA) from 2002 to 2019 to explore import refusals based on contamination with pathogens and toxins.

From 2002 to 2019, most pathogen/toxin violations occurred in fishery and seafood products (44.1 percent), followed by spices, flavors, and salts (26.3 percent), cheese and cheese products (7.1 percent), fruit and fruit products (6.2 percent), and nuts and edible seeds (5.1 percent).

Salmonella was the most common type of pathogen/toxin violation for fishery and seafood products; spices, flavors, and salts; fruit and fruit products; and nuts and edible seeds. Listeria was the most common type of pathogen/toxin violation for cheese and cheese products, the report noted.

While data capable of estimating the risk of foodborne illness to US consumers from foreign producers is limited, US import refusal data list the most common reasons foreign shipments were refused, the report noted. FDA physically examines approximately 1 to 2 percent of imports.

All imports are electronically screened using an automated system called Predictive Risk-based Evaluation for Dynamic Import Compliance Targeting (PRE-DICT). FDA inspects imports for signs of adulteration or misbranding. Import refusals are recorded in the Operational and Administrative System for Import Support (OASIS) database where each entry has a violation code, industry group, and country of origin.

Even though OASIS is a rich data set for import refusal, it has limitations, the ERS report noted. First, the total volume or value of each shipment is not revealed, so it is hard to identify which product had the largest threat to food safety for the US market. Second, FDA does not randomly choose a sample to inspect; the inspectors choose a sample based on informed choice from their previouis experiences.

Despite these limitations, OASIS data continuously recorded shipment refusal over decades, which makes them useful for analyzing trends and patterns of imported food both inspected and refused by FDA.

The ERS report examines the number of import refusals for various bacteria (e.coli 0157), Listeria, Salmonella, Shigella, and Vibrio), a virus (Hepatitis A), and some toxins (aflatoxin, histamine, and patulin) from 2002 to 2019. These types of refusals are referred to as pathogen/toxin violations.

Refusals By Pathogen, Industry

From 2002 to 2019, 22,459 pathogen/toxin violations were detected.

The majority of them, 17,922, had the presence of Salmonella, which accounts for 79.8 percent of the total pathogen/toxin violations.

Listeria is next with 2,463 cases (11 percent), followed by histamine, aflatoxin, and other bacteria with 804 (3.6 percent), 663 (3 percent), and 455 violations (2 percent), respectively. The rest of the refused shipments due to other pathogens numbered just 153 cases.

Compared to the previous ERS report (2008), the share of Salmonella violations increased from 63 percent over the 1998-2004 period to 79.8 percent over 2002-19. Listeria violations decreased from 24.8 percent over 1998-2004 to 11 percent over 2002-19.

Refusals because of Salmonella increased from 924 violations in 2009 to 2,258 violations in 2011. These spikes were largely driven by fishery and seafood products, and fruits and fruit products.

After that spike, Salmonella violations continuously declined over time. One possible explanation for the continuous decline in import refusals, according to the report, is the Food Safety Modernization Act (FSMA), which substantially expanded and modified FDA’s previous authority to enhance its oversight of imported food. As a result, FSMA could provide PREDICT with more data on imported food.

As far as the remaining four leading pathogen/toxins, Listeria, histamine, aflatoxin, and other bacteria have either trended downward or remained relatively stable.

The notable exception is the decline in Listeria violations from 300 cases in 2003 to 68 cases in 2007. This plunge mainly came from a large Listeria decrease in cheese and cheese products.Listeria violations, like Salmonella, increased during 2010-12.

Following the two most frequent industries, cheese and cheese products, fruits and fruit products, nuts and edible seeds, and vegetables and vegetable products each accounted for more than 4 percent of the total violations. Each of the remaining industries accounted for less than 2 percent of violations.

Overall, Salmonella was the most common violation in each industry except cheese and cheese products, in which Listeria had the most violations.

Salmonella and Listeria are the main drivers for the seven industry groups most frequently noted for pathogen/toxin violations. The cheese industry accounted for the largest portion of pathogen/toxin violations because of Listeria in the early 2000s, the report said. Average Listeria violations of cheese products fell from 150 in the early 2000s to 12 in the late 2010s.

Over the study period, 110 countries had at least one pathogen/toxin violation. India had the most pathoge-related violations with 5,115 refusals, followed by Mexico with 3,338 violations. Vietnam and Indonesia followed with more than 1,700 refusals over the study period. And France had 971 refusals over the period.

Except for France, Salmonella caused the majority of refusals in the other 16 countries that accounted for 1 percent or more import refusals. Of the 971 pathogen/toxin violations found from France, Listeria accounted for 863 violations, or 88.9 percent.

One possible explanation why many cheese products from France were refused is due to close monitoring of Listeria by FDA, the report said. The largest number of cheese products made from raw milk came from France and, according to the CDC, soft cheeses made with raw milk are more likely to be contaminated by Listeria than other pathogens, such as Salmonella.