Identification of Mammalian and Poultry Species in Food and Pet Food Samples Using 16S rDNA Metabarcoding

Laura Preckel,Claudia Brünen-Nieweler,Stefanie Dobrovolny,Grégoire Denay,Henning Petersen,Margit Cichna-Markl,Rupert Hochegger

doi:10.3390/foods10112875

Abstract

The substitution of more appreciated animal species by animal species of lower commercial value is a common type of meat product adulteration. DNA metabarcoding, the combination of DNA barcoding with next-generation sequencing (NGS), plays an increasing role in food authentication. In the present study, we investigated the applicability of a DNA metabarcoding method for routine analysis of mammalian and poultry species in food and pet food products. We analyzed a total of 104 samples (25 reference samples, 56 food products and 23 pet food products) by DNA metabarcoding and by using a commercial DNA array and/or by real-time PCR. The qualitative and quantitative results obtained by the DNA metabarcoding method were in line with those obtained by PCR. Results from the independent analysis of a subset of seven reference samples in two laboratories demonstrate the robustness and reproducibility of the DNA metabarcoding method. DNA metabarcoding is particularly suitable for detecting unexpected species ignored by targeted methods such as real-time PCR and can also be an attractive alternative with respect to the expenses as indicated by current data from the cost accounting of the AGES laboratory. Our results for the commercial samples show that in addition to food products, DNA metabarcoding is particularly applicable to pet food products, which frequently contain multiple animal species and are also highly prone to adulteration as indicated by the high portion of analyzed pet food products containing undeclared species.

Highlights

Commercial food and feed products must meet the requirements of national and international regulations
We evaluated whether the results obtained by DNA metabarcoding were in line with sample composition or declaration
In addition to DNA metabarcoding, each sample was analyzed by real-time PCR and/or a commercial DNA array to evaluate the reliability of the DNA metabarcoding method

Summary

Introduction

Commercial food and feed products must meet the requirements of national and international regulations. Food fraud has become a global issue, with meat products being vulnerable to adulteration [1]. Meat products are frequently found to be adulterated by substitution of animal species given on the label by animal species of lower commercial value [2]. DNA-based methodologies make use of genetic variations between species, e.g., single nucleotide polymorphisms (SNPs), insertions and deletions. They target either species-specific fragments in nuclear DNA or conserved regions in the mitochondrial genome. DNA arrays and real-time PCR assays are mainly used for the authentication of meat products in official food laboratories

Methods

Results

Conclusion