The day after the U.S. Food and Drug Administration issued a warning for pet owners earlier this month, pet food manufacturer Lystn LLC fought back, claiming samples that tested positive for Salmonella could have been contaminated in a lab used to test the dog food.

Lystn, the manufacturer of Answers Pet Foods, offers a range of raw pet foods “enhanced” with kombucha, raw cultured whey, cultured raw goat’s milk and kefir. According to the company, the probiotic bacteria in the fermented ingredients offer protection against Salmonella.

Lystn describes this approach on its website as “safety through inhibition” and claims the fermentation process to be the “most natural and effective way” to make their products “as safe and healthy as possible.”

In 2009, A.R. Hoyle and co-workers reported that lactic acid bacteria could decrease the numbers of Salmonella and E. coli O157:H7 in ground beef during storage. However, several studies have shown that use of lactic acid bacteria is most effective when incorporated into a combined strategy employing other complementary treatments.

On Dec. 10, 2018, the Nebraska Department of Agriculture (NDA) obtained a random sample of A+ Answers Straight Beef Formula 4lb. Pounder for Dogs, Lot 2018 02/08 20. On or about Dec. 20, NDA advised both Lystn and the FDA that it had found Salmonella in the sample.

Lystn requested and received from the NDA a split sample of the implicated lot, and confirmed the presence of Salmonella in this sample, according to the company’s statement. A second split sample provided to Lystn by NDA at the company’s request produced a negative result.

In its press release, Lystn expressed its “belief” that the initial split sample provided by the NDA “. . . may have been cross contaminated in the lab, transport or elsewher and should not be considered a representative sample.” The company offered no evidence to support the assertion.

Lystn also disputed the appropriateness of FDA’s zero tolerance policy for Salmonella in raw pet food.

No FDA spokesperson was available for comment because of the partial government shutdown.

The NDA inspector and lab personnel used appropriate chain-of-custody procedures for handling the pet food sample, according to a spokesperson for the state. The sample was handled and analyzed in a Biosafety Level 2 (BSL-2) lab, under full compliance with all sanitation and handling procedures.

No other testing was performed in the lab at the same time. Access to a BSL-2 lab is restricted while testing is being conducted in order to limit any possible risk of inadvertent contamination of the sample, the environment, or personnel, according to the U.S. Centers for Disease Control and Prevention (CDC) website.

The lab personnel used both positive and negative controls as part of their testing protocol, and submitted the purified Salmonella culture to the Nebraska Public Health Laboratory (NPHL) for molecular testing. NPHL identified the culture as Salmonella Cerro. The positive control used as part of the testing procedure was Salmonella Arizonae.

According to Lystn, the company stopped distribution of the lot in question, and the product was removed from retail store shelves within the state of Nebraska.

Although Lystn asserted in its Jan. 15 statement that the product was not recalled, the company’s action met FDA’s definition of a product recall, which is “. . . a firm’s removal or correction of a marketed product that the FDA considers to be in violation of the laws it administers and against which the agency would initiate legal action.”

The company chose not to implement a nationwide recall of the contaminated production lot, as the product was only tested by NDA and not by FDA, according to the Lynst statement.

Lystn’s customers are welcome to return any unused portion of the affected product for full refund, according to the company’s press release, which stated “. . . if a customer is uncomfortable with an ANSWERS’ product, they may return it, or any unused portion, to the place of purchase for a full refund. The Straight Beef Formula 4lb. Pounder for Dogs product comes in a cardboard milk carton box marked with lot code 2018 and a Best Use By Date (BUBD) of 02/08 20 sticker on the carton.”

The implicated lot was distributed from Aug. 17, 2018 to Sept. 14, 2018, and sold through retail stores within the United States.

A Lystn spokesperson was unable to release further details at this time, stating that the company was in the process of completing its investigation on the products from NDA as well as working with FDA.