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Harvest facility pathways for African swine fever

UMN Secure Food Systems analysis finds biosecurity gaps in procedures where risk assessments should be conducted, additional mitigations be developed.

Ann Hess

October 3, 2022

7 Min Read
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If African swine fever were introduced into the United States, the pork industry would face a major disruption to everyday activities. To protect the industry and the supply of pork products, the industry needs to be prepared at every step along the pig life cycle, said Catherine Alexander, a researcher with the University of Minnesota Department of Veterinary and Biomedical Sciences, and those steps need to include inputs and outputs from pork harvest facilities.

During last month's Allen D. Leman Swine Conference, Alexander highlighted a pathway analysis the UMN Secure Food Systems recently conducted with two Midwest pork harvest facilities. The project scope was limited to facilities that conduct on-site slaughter and include primal cuts among their products. In addition to collaboration with the two facilities, which were assumed to be representative of the industry and its standards, the project also included literature searches for regulations and practices within the pork processing industry.

"The objectives were, first of all, to determine the inputs and outputs of the pork harvest facilities. So, in other words, pathways of ASF virus introduction and spread," Alexander said. "And then with the input from the industry, assign priorities for further risk assessment based on the perceived risk of each of those pathways."

Through meetings with facility experts from both harvest facilities, animal, people and product inputs/outputs were determined. The identified pathways were scrutinized so further categorization of practices and procedures as mitigated, unmitigated or unknown could be defined.

Alexander said the definitions included describing any existing mitigations within the pathways, which allowed for a detailed explanation of areas where additional biosecurity mitigations could be implemented in the event of an ASF outbreak.

A priority rating was then assigned to each pathway based on the perceived risk determined by the presence or lack of mitigations, potential consequences and the likelihood of potential ASF virus spread for determining the highest need for pursuing further risk assessments.

The research team found six input pathways, including but not limited to people, equipment and pigs for slaughter, and 16 output pathways, including but not limited to products, laundry and waste, were potential pathways for virus introduction and spread. The majority of pathways were either somewhat unmitigated, completely unmitigated or unknown if mitigated.

The six input pathways are:

  • People, USDA Food Safety Inspection Services inspection personnel, visitors- Somewhat mitigated

  • Pigs for slaughter- Unmitigated (high risk)

  • Vehicles- Unmitigated (high risk)

  • Equipment/supplies- Somewhat mitigated

  • Water- Mitigated

  • Pests- Mitigated

"The pathways that are considered fully mitigated have mitigations that support the inactivation and or exclusion of the virus," Alexander said. "For example, pests and water have enough regulation to consider these pathways as mitigated. Harvest facilities are required to have pest management programs in place to prevent pests and breeding of pests on the premises. Also, through discussion with our collaborators, we determined that most harvest facilities or the majority all use municipal water sources, so treated water. Again, this is also supported by the code of federal regulations, which provides additional details about the requirements for clean water for use within the harvest facilities."

For the pathways considered somewhat mitigated, Alexander said the team found those pathways to either have a mixture of mitigated and unmitigated components or the mitigations may not entirely support the inactivation or exclusion of the ASF virus. For example, with people and personnel, there are some federal regulations that dictate personal hygiene and hygiene while working at the plant, but there's a lack of restriction, in general, regarding contact with other pigs.

"Our work with the collaborators showed that most harvest facilities likely do not have requirements such as mandatory downtime after contact with outside pigs, the unmitigated pathways have no standard mitigations and as a result, there are areas of risk for virus introduction into the harvest facility," Alexander said. "When pigs go to the plant for processing, sick pigs may not be truly segregated from the rest of the pigs before they're euthanized and sent to rendering."

In addition, there are few regulations for pig holding, aside from ensuring that the bedding is being cleaned at a high enough frequency to keep things clean.

"The bedding may be used between loads with little maintenance in between and this lack of mitigation shows a gap in biosecurity where the virus could spread within the plant if an infected, but undetected, pig gets brought into the plant," Alexander said.

Vehicles are another unmitigated pathway as employees, visitors and FSIS personnel often use the same parking lot, and there are no restrictions for vehicles.

"They may come from different locations that house live pigs," Alexander said. "Also, the FSIS personnel may visit multiple plants without any vehicle cleaning or disinfection in between, and live haul vehicles do not have requirements for undercarriage or tire cleaning prior to, or at the time of arrival, at the facility. So, these vehicles may have come from different locations with live pigs, and they continue to go on to additional locations where there are also live pigs."

For the 16 main output pathways, Alexander said these represent ways that the virus could be spread from the plant, if an undetected ASF infected pig was processed.

"Output pathways have more uncertainty, as many product processes are facility specific. The processes for products such as ready-to-eat products tend to be proprietary. Thus, we're unable at this time to determine what, if any, mitigations are in place for those outputs," Alexander said. "Live haul vehicles, people, waste in the form of manure and garbage are the pathways where we perceive there to be the highest risk for the spread of the virus from the plants."

The 16 output pathways are:

  • Live resale pigs- Unmitigated

  • People- Unmitigated (high risk)

  • Raw edible finished- Unmitigated (high risk)

  • Vehicles- Live haul- Unmitigated (high risk)

  • Manure garbage- Unmitigated (high risk)

  • Ready to eat- Unknown

  • Raw inedible- Unknown

  • Hides- Unknown

  • Citrated plasma- Mitigated

  • Vehicles for people- Unmitigated

  • Wastewater/manure in wastewater- Mitigated

  • Raw edible-unfinished- Unknown

  • Rendered products- Mitigated

  • Organs/glands for pharmaceuticals- Unmitigated

  • Casings- Mitigated

  • Laundry- Unknown

With a majority of the output pathways largely unmitigated, the potential for virus spread is quite high, Alexander said. For example, often live haul vehicles do not have cleaning and disinfection requirements when they leave the processing plants. Since plants don't typically have truck washes on site, and then the loading docks are not usually cleaned between loads of pigs, this creates a potential for cross contamination of the trucks, she said.

Employees from the different sections of the plant are also not entirely segregated, as kill floor employees and cut floor employees may share break and/or locker rooms, and they all leave the plant floor from the same general area. Management is also not entirely segregated from the floor employees.

"FSIS inspectors may go from plant to plant with no known mitigation between those visits, such as a shower or change of clothes on entering the plant operations,"Alexander said. "Although they do have required change of clothing before performing and after completing antemortem inspections."

Finally, Alexander said manure and bedding typically go to a landfill and there are few to no mitigations in place for those leaving the harvest facilities and the same goes for garbage.

"There may be virus in the manure or the bedding, or even in the garbage that's then being transported to landfills," Alexander said.

With the resale of live pigs and the high risk of spreading the virus from the plant, Alexander said during a stop movement from an active ASF outbreak, it would probably be more expeditious and economical for the plants to render those pigs.

"Companies themselves will need to determine where they need to apply additional mitigations, or possibly stop shipping certain products off site if they are unsure about whether or not the virus could spread. A lot of that depends on their individual processes for how they process certain products at the plant," Alexander said.

Of the 22-disease transmission and spread pathways identified, 50% are at least partially, if not entirely, unmitigated. Examination of these pathways revealed gaps in existing procedures that have the potential for ASF virus transmission and spread, Alexander said, and are areas where risk assessments should be conducted, and additional biosecurity/risk mitigations should be developed.

"Only six of 22 pathways were determined to be fully mitigated and to have a low perceived risk of introducing or spreading the virus from the harvest facility. The other 16 pathways still have gaps and present risk, and that's about 73% of the pathways," Alexander said. "Again, these are preliminary results. We're still working with the companies and gathering more information on these pathways, but one thing is that these gaps do point out areas for the plants where they can hone in and focus on enhanced biosecurity, or different processes for their products."

About the Author(s)

Ann Hess

Content Director, National Hog Farmer

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