NGS-based barcoding with mini-COI gene target is useful for pet food market surveys aimed at mislabelling detection

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.

Detection of chicken DNA in commercial dog foods

“…The studies of Dunham-Cheatham et al [25] have shown that adulteration is common in commercial pet food. This fact is confirmed by the analyzes of Palumbo et al [24] who found that 16 of 18 commercial pet foods tested were adulterated. Both studies have shown that ingredients with higher economic value (e. g. fish) are often supplemented or completely replaced with ingredients with lower economic value (e. g. chicken).…”

“…In recent years, many techniques have been developed to allow food traceability through DNA barcoding techniques even for complex and highly processed mixtures such as pet food. These techniques can identify adulteration in pet food products, which are an increasing problem among consumers and underpin several lawsuits in recent years [23,24]. Properly selected methods can also provide a way to confirm that pet food is indeed "grain free", "corn free" or "chicken free" for example, claims that are becoming more common in many commercial pet products [25].…”

MetaCOXI: an integrated collection of metazoan mitochondrial cytochrome oxidase subunit-I DNA sequences

“…In order to exclude very short sequences, nuclear genomes and genomic scaffolds, only sequence lengths ranging from 100 bp to 60 kbp were considered (the latter being the approximate length of the longest mitochondrial genome reported to date ( 26 )). The selected short fragments (less than 500 bp) would potentially benefit the experiments based on DNA mini-barcodes ( 27 , 28 ) or on reads of typical HTS outputs ( 29 ). To avoid the presence of stop codons and to increase the accuracy of matching with the reference COXI profile, all DNA sequences were translated into amino acids, with a custom python script (newTranslator_CExtract.py), using their corresponding mitochondrial genetic code (retrieved from NCBI taxonomy dump files: https://www.ncbi.nlm.nih.gov/taxonomy ) and all six open reading frames.…”

Preliminary study on species authentication in poultry meat products by next-generation sequencing

“…Thank to these new generation of sequencers, all the DNA molecules extracted from the matrices can be simultaneously amplified and sequenced allowing species identification also in complex foods containing multiple ingredients. Although application of metabarcoding to trace ingredients is still in its infancy, several studies have tested this approach for species identification in different food products including dairy (Ribani et al, 2018), seafood (Giusti et al, 2017;, commercial plant (Bruno et al, 2019), herbal medicinal (Anthoons et al, 2021), candies (Muñoz-Colmenero et al, 2017) honey (Prosser & Hebert, 2017;Wirta et al, 2021), probiotics (Patro et al, 2016) and pet food (Palumbo et al, 2020;Preckel et al, 2021). Few studies applied metabarcoding to investigate the species composition in artificially prepared mixtures or commercial meat and meat products (i.e., sausages, balls, canned luncheon meat, minced meats, kebab) made of several animal species including beef, camel, horse, sheep, deer, swine and/or poultry (Cottenet et al, 2020;Dobrovolny et al, 2019;Pan et al, 2020;Preckel et al, 2021;Xing et al, 2019).…”