Abstract
Pet food industry has grown considerably in the last few years and it is expected to continue with this rate. Despite the economic impact of this sector and the consumer concerns for the increasing number of food and feed adulteration cases, few studies have been published on mislabelling in pet foods. We therefore investigated the capability of a next generation sequencing-based mini-barcoding approach to identify animal species in pet food products. In a preliminary analysis, a 127 bp fragment of the COI gene was tested on both individual specimens and ad hoc mixed fresh samples used as testers, to evaluate its discrimination power and primers effectiveness. Eighteen pet food products of different price categories and forms available on the market (i.e. kibbles, bites, pâté and strips) were analysed through an NGS approach in biological replicates. At least one of the species listed in the ingredients was not detected in half of the products, while seven products showed supplementary species in addition to those stated on the label. Due to the accuracy, sensitivity and specificity demonstrated, this method can be proposed as food genetic traceability system to evaluate both the feed and food quality timely along the supply chain.
Highlights
Pet food industry has grown considerably in the last few years and it is expected to continue with this rate
The total gDNA extracted from the 10 fresh meat samples, 18 discount/premium pet food (PF) products and ad hoc mixtures (35 samples in total, including the replicates a and b, when available), had a mean concentration of 819 ng/μL and absorbance ratios at 260/280 nm between 1.5 and 1.8
DNA integrity was very poor in the pet food samples, with most products having DNA fragments in the gel of 300 bp or less, but consistently higher in the fresh meat samples and ad hoc mixtures, where the molecular lengths were over 10 kb
Summary
Pet food industry has grown considerably in the last few years and it is expected to continue with this rate. DNA barcoding has been largely applied to different food sectors, studies on the traceability and mislabelling of pet foods are still scarce and generally performed on single species-based products using direct Sanger sequencing[23,24,25,26] or multiple species with qPCR assays[9]. To the best of our knowledge, the study by Xing et al represents the first (and, so far, only) attempt to investigate the species composition of pet food products by means of NGS-based DNA m etabarcoding[27], even though almost all of the products analysed (26 of 27) were for human consumption and the species within the products were limited to the Aves and Mammalia classes Overall, these studies highlighted an impressive rate of pet food mislabelling that ranged from 38%9 to 100%24
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