Mislabeling seems to be a widespread issue in pet foods, research in Italy has found, posing problems for those aiming to exclude a particular meat source from their pet’s diet.
Although the European Pet Food Industry Federation stated that labels must be accurate and provide detailed information on the ingredients, mislabeling of pet food has been documented by several researchers.
The issue is of concern to those requiring a controlled diet for their pets, according to Rebecca Ricci and her colleagues, writing in the journal BMC Veterinary Researchers.
In a British study, when testing for the presence of beef, chicken, pork and horse DNA in 17 popular wet pet foods obtained from supermarkets, researchers found that cow, pig and chicken were included in 15 of them, even when not explicitly stated on their labels.
Similarly, when testing 52 dog and cat foods available in the US market for eight different animal species, researchers found that 38.5% of pet foods were potentially mislabeled because they either contained meat species not declared in the label or did not contain meat species that were.
The issue is of particular concern when pet-food products are used as elimination diets to help diagnosis adverse food reactions in dogs and cats, because the presence of undeclared ingredients may interfere with the trial.
Ricci and her colleagues set out to shed light upon the problem of contamination and mislabeling in both dry and wet novel protein diets, and hydrolyzed protein diets, testing for DNA from 19 animal species (beef, buffalo, cat, chicken, dog, donkey, duck, hare, fish, goat, goose, horse, mice, porcine, poultry, rabbit, rat, sheep and turkey).
A total of 40 pet foods formulated as suitable for the diagnosis of adverse food reactions were collected from the market – 36 for dogs and four for cats. They were produced by 14 different producers. Fifteen of the products were dry foods; 25 were wet.
Labels were carefully read to identify every source of protein and fat in the ingredients list. Then, a 50 gram sample from each underwent laboratory analysis.
Of the 40 analyzed products, ten had content that correctly matched the label, while five did not contain one of the declared animal species at all, 23 revealed the presence of undeclared animal species, and two had a vague label that did not allow the evaluation of its accuracy.
The most frequent contaminants identified in both dry and wet pet foods were pork, chicken and turkey.
The presence of undeclared animal species was higher in dry than wet pet foods.
Mislabeling seems to be a widespread issue in pet foods used as elimination diets, they said.
“Due to the high risk of contamination, particular attention should be given to both the selection of raw material suppliers and the production process.”
Beef, chicken, duck, fish, goat, goose, horse, pork, poultry, rabbit, sheep and turkey were detected in at least one sample of the pet foods tested. Buffalo, cat, dog, donkey, hare, mice and rat were not detected in any samples.
Among the 15 dry foods tested, 11 of them did not list horse as an ingredient. However, horse DNA was detected in three of them (27.3%). Among the 25 wet foods, 21 of them did not list horse as an ingredient, but one sample tested positive for horse DNA.
The most common contaminants (that is, meats not listed on the label) in dry pet foods were pork, chicken, poultry and turkey, followed by bovine, fish and ovine, then horse. On the other hand, the least common contaminants were duck and goat.
Regarding wet pet foods, pork was the most common contaminant, followed by chicken, poultry, turkey, bovine and sheep. The least common contaminant was horse, while fish, duck and goat were not detected in these samples.
In the end, only 25% of the products analyzed were suitable for effective adverse food reaction (AFR) diagnosis.
“Although these findings demonstrate that producing an uncontaminated pet food is possible, three out of four commercial elimination diets would not be useful in allowing the clinician to obtain precise AFR diagnosis.”
They continued: “Particular attention should be given to both the production process due to the high risk of cross-contamination and the selection of raw material suppliers.
“Bearing this in mind, these results reflect the contamination of only the batches collected here, and therefore the mislabeling of a specific product cannot be generalized either to the respective producer’s previous or future productive lots.
“Importantly, this study demonstrates that the production of uncontaminated products is possible, as confirmed by the 10 pet foods (26%) that analysis found to be correctly labeled.
“When an adverse food reaction is suspected, a home-made elimination diet may be a reasonable alternative to commercial products because it allows a stricter control of the ingested ingredients and highly reduces the risk of contaminants that pose risks to the correct diagnosis of AFR.”
The study team comprised Ricci, Daniele Conficoni, Giada Morelli, Carmen Losasso, Leonardo Alberghini, Valerio Giaccone, Antonia Ricci and Igino Andrighetto.
Undeclared animal species in dry and wet novel and hydrolyzed protein diets for dogs and cats detected by microarray analysis
Rebecca Ricci, Daniele Conficoni, Giada Morelli, Carmen Losasso, Leonardo Alberghini, Valerio Giaccone, Antonia Ricci and Igino Andrighetto
BMC Veterinary Research 2018 14:209 https://doi.org/10.1186/s12917-018-1528-7