Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Research Project #435156

Research Project: Trichinella Testing Laboratory

Location: Animal Parasitic Diseases Laboratory

Project Number: 8042-32420-007-31-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jul 16, 2018
End Date: Sep 30, 2020

Objective:
Pork has been subject to food safety concerns since the discovery, in the late 1800’s, that it can be a source of infection for the nematode parasite Trichinella. Over time, requirements have been imposed on U.S. pork to address risks associated with this parasite. While, historically, these actions reflected valid public health concerns, Trichinella has essentially disappeared from modern pork production systems. Unfortunately, trade requirements and even domestic food safety regulations do not reflect this change in risk. Multiple U.S. trading partners ask for assurances of safety, such as industry-wide testing results, but these data do not exist. Some trading partners continue to require freezing, cooking or even individual carcass testing per the World Organization for Animal Health (OIE) as a risk mitigation, thereby severely limiting the opportunity to export high-value fresh chilled pork. In a strategy to overcome these export limitations, the National Pork Producers Council (NPPC) and the National Pork Board (NPB), working together with the United States Department of Agriculture (USDA), have been able to introduce and secure language into international food safety standards that allow countries to define their commercial pork as having a “negligible risk” for Trichinella infection. The purpose of this new risk classification is to ensure consumer health and standardize requirements for international trade. Exported pork originating from a herd classified as negligible risk will not be subject to any additional testing or processing mitigations (e.g., freezing, cooking or individual carcass testing) for Trichinella. The negligible risk production standards of the OIE (Annex 1) address the risk factors for exposure of pigs to Trichinella. Compliance with these production standards eliminates risk of exposure to Trichinella if it were present in the environment. The U.S. pork industry and USDA consider pork production sites with Pork Quality Assurance (PQA) Plus® status to be eligible for classification as negligible risk. All herds classified as negligible risk would then be eligible for inclusion in a “compartment” of negligible risk. A compartment of negligible risk for Trichinella, as defined by Codex, is “an animal subpopulation contained in one or more establishments”, that are raised under conditions of controlled management. Pork originating from a compartment of negligible risk would not be subject to any Trichinella testing or mitigation requirements for the purpose of trade. A prerequisite to establishing a compartment of negligible risk for Trichinella in the U.S. requires documentation that Trichinella infection is absent or at a very low prevalence (< 1/M pigs) in the compartment. Testing must be performed for a period of not less than 24 months, and must be performed using an internationally accepted testing methodology. The test procedure is the pooled sample digestion method, as specified in the World Animal Health Organization (OIE) Manual of Diagnostic Tests and Vaccines, and is approved by the USDA and the European Union.

Approach:
The number of samples required per facility will be determined based on participation. Assuming a population size of 80M pigs, the total number of samples to be tested each year is approximately 3,000,000 equating to a total of 6,000,000 samples over the two-year period that surveillance is to be conducted. Samples will be collected from PQA Plus® pigs only. Sampling protocols will be provided to guide the collection process as well as identification required for collected samples. Each facility will have a weekly goal. Samples can be collected at any time during the week to meet these sampling goals. The required sample is a piece of muscle tissue cut from the crus (hanging tenderloin), which is most easily collected following carcass split and evisceration. Sample size must be at least two grams, but should not exceed five grams. The testing laboratory is currently evaluating tools that packers might use to simplify and standardize collection. Each group of 100 samples collected will be placed into a single one-gallon plastic freezer bag and the bag marked to indicate the lot or lots included. Collection bags and shipping materials will be provided by the testing facility and included in the cost of testing. Collected samples will be shipped daily to the testing facility or may be retained at refrigerated temperatures for up to five days prior to shipping. Samples will be processed as they are received by the testing facility. The testing protocol is the Pooled Sample Digestion Method.