Animal & Veterinary

CVM Issues Assignment to Collect and Analyze Samples of Pet Foods, Pet Treats, and Pet Nutritional Supplements for Salmonella


Date: December 16, 2013


Certain food for animals, such as pet foods, pet treats, and pet nutritional supplements pose a risk to human health when contaminated with Salmonella, because humans come in direct contact with these pet foods, pet treats, and pet nutritional supplements. Salmonella from such pet foods, pet treats, and pet nutritional supplements may be ingested directly by humans from their hands or utensils that are contaminated when they feed their pets. Certain vulnerable populations, such as children, the elderly, and individuals with compromised immune systems, are particularly susceptible to acquiring salmonellosis from pet foods, pet treats, and pet nutritional supplements, and may experience more severe symptoms. Additionally, animals may become infected, either asymptomatically or clinically with Salmonella from these pet foods, pet treats, and pet nutritional supplements thus increasing the potential human exposure.

The association between human outbreaks of salmonellosis and contact with Salmonella-contaminated pet foods and pet treats is well established. Health Canada informed FDA of Canadian outbreaks of human salmonellosis that were linked to Salmonella Infantis in pig-ear dog treats that were manufactured in Canada in 1999 and to Salmonella Newport in beefsteak-patty dog treats that were manufactured in Texas in 2002. In addition, human outbreaks of salmonellosis in Canada and the United States in 2005 were linked to pet treats contaminated with Salmonella Thompson. Moreover, the Centers for Disease Control and Prevention (CDC) reported that, from January 1, 2006 to October 31, 2008, 79 human cases of salmonellosis were linked to Salmonella Schwarzengrund in dry dog foods that were manufactured by a company in the United States. More recently in 2012, 49 individuals were infected with Salmonella Infantis, which was linked to dry dog food manufactured by a company in a single facility in South Carolina.

FDA believes regulatory action is warranted in cases involving pet foods contaminated with any Salmonella serotype, due to the heightened human health risk given the high likelihood of direct human contact with such foods. For these reasons, the Center for Veterinary Medicine (CVM) considers it prudent to keep Salmonella-contaminated pet foods, pet treats and pet nutritional supplements out of interstate commerce.


  1. To determine the prevalence of Salmonella in samples collected from a limited number of pet foods, pet treats, and pet nutritional supplements; and,
  2. To determine the serotype, genetic fingerprint, and antimicrobial susceptibilities of each isolate of Salmonella found in samples collected from pet foods, pet treats, and pet supplements under this assignment; and,
  3. To ensure that Salmonella-contaminated pet foods, pet treats, and pet nutritional supplements are removed from interstate commerce.


All samples under this nationwide assignment will be collected from pet foods, pet treats and pet nutritional supplements manufactured in the United States. This assignment does not cover imported products in either import status or domestic import (D/I) status.

Resources have been allocated under the fiscal year (FY) 2014 work plan for FDA districts to collect and analyze 300 official samples of pet foods, pet treats and pet nutritional supplements for Salmonella (see table below for details). There will no investigational samples collected as part of this assignment in FY 2014.

Sample Type Total # of Samples Collected Hours per Sample Collection PAC Sample Size Controls Collected Interstate Commerce Documented
Official 300 4.2 71003E 10 subs
200 g/sub from same lot
Yes Yes

The samples can be collected at the manufacturer, distributor, wholesaler, or retailer in which pet foods, pet treats, and pet nutritional supplements are manufactured, held or offered for sale or for consumption. Each district should make every reasonable effort to collect pet nutritional supplement samples from a manufacturer or distributor. This will help ensure that an adequate number of subsamples of the product (vitamins, minerals, fish oils, antioxidants, etc.) with the same lot is available. If possible, a variety of products from different manufacturers and sources should be selected to support efforts to determine nationwide prevalence. An effort should be made to target as many new manufacturers, distributors, wholesalers, or retailers as possible. This assignment, however, does not cover canned pet foods.

Packaged samples shall be collected in accordance with IOM Chapter 4.3. Investigators are further instructed to make every reasonable effort to collect all interstate documentation, identify the manufacturer, distributor and the shipper of the products and report this on the FACTS Collection Report. Additionally, those samples collected that are not contained in a consumer package, i.e. bulk rawhides, etc., shall be collected aseptically as instructed in IOM Chapter 4.3.6.

For this assignment, each official sample should consist of 10 sub-samples with each weighing approximately 200 g. Each of these 10 sub-samples already includes the 702(b) portions.


Handle, identify, package and ship samples in ways to ensure sample integrity. Deliver samples to the laboratory promptly with the original storage conditions maintained as nearly as possible. Please refer to IOM, Subchapter 4.5, for details about sample preparation, handling, and shipping. Samples collected under this assignment will, in general, not require refrigeration, and should be shipped by overnight to the laboratory as soon as possible after collection. In those occasional instances where refrigeration may be indicated (e. g., moist feed), investigators should refer to the IOM at


Ship official samples to the identified servicing laboratories on the (FY) 2014 work plan for your specific District for analyses of Salmonella.

Do not ship on Friday for Saturday delivery. Contact the sample custodian and notify them of the shipment of the sample.


Official samples: FDA’s servicing laboratories will analyze the official samples of pet foods, pet treats, and pet nutritional supplements for Salmonella. In this assignment, servicing laboratories will NOT analyze the 300 official samples for E. coli O157:H7.

AOAC Official Method 2004.03 [Determination of Salmonella in Foods by VIDAS (SLM) Immunoassay], an enzyme-linked immuno-fluorescent assay or 2011.03 VIDAS SLM EASY are to be used as the screening methods for this assignment. Refer to procedures outlined in the FDA’s Bacteriological Analytical Manual (BAM) on line, Feb. 2011, chapter 5, Salmonella for the confirmatory method to use in this assignment.

Aseptically weigh approximately 37.5 g (~ 1.3 oz) from each of the 10 sub-samples to form a 375 g (13.2 oz) composite sample for Salmonella analysis. Prepare pet treats and chews for Salmonella analysis using the procedures outlined in the BAM, chapter 5, section C (Preparation of foods for isolation of Salmonella), sub-section 20 (Pig ears and other types of dog chew pieces).

Reserve approximately 75 grams (~ 2.6 oz) or more from each of the 10 sub-samples for use as the 702(b) portion. Each of these 10 sub-samples already includes the 702(b) portions so there is no need to collect additional 702(b) portions per 21 CFR 2.10 (b)(3).

If a sample is positive for Salmonella, the servicing lab will send each Salmonella isolate to DEN-LAB for serotyping and antimicrobial-susceptibility testing.

In addition, each servicing laboratory will conduct a pulsed-field gel electrophoresis (PFGE) analysis on each Salmonella isolate found under this assignment. The servicing lab will email the PFGE image(s) with FACTS sample numbers to CVM Office of Research (CVM-OR) to upload the PFGE image(s) of each Salmonella isolate found under this assignment into the CDC PulseNet database.


The Center for Veterinary Medicine (CVM) intends to support advisory/regulatory action against pet foods, pet treats, and pet nutritional supplements if they are found to be contaminated with Salmonella, and their manufacturers, for which interstate commerce can be documented under this assignment. Regulatory Action Guidance is provided in the Compliance Policy Guide Sec. 690.800 Salmonella in Food for Animals.

For each official sample of pet foods, pet treats, and pet nutritional supplements found to contain Salmonella, districts should initiate procedures to remove the contaminated pet foods, pet treats, and pet nutritional supplements from interstate commerce, to inform the responsible firm of the need to initiate corrective action to prevent future contamination, and to recommend the issuance of a Warning Letter. In addition, within 90 days of being informed by the laboratory of the finding of Salmonella in a sample, CVM will request the district, in which the manufacturing firm/importer is located, to conduct follow-up investigations of the facility or facilities where the violative sample was manufactured to review manufacturing and handling procedures, document what corrections, if any, were made, and collect follow-up samples.

CVM will evaluate the information provided in a district's recommendation for advisory/regulatory action.

Daniel G. McChesney, Ph.D.
Director, Office of Surveillance and Compliance

Page Last Updated: 06/05/2014
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