Mammalian and avian species quantification in homogenized foods: real time PCR and digital PCR as tools for label compliance controls

TL;DR

This study compares Real Time PCR and Digital PCR for detecting chicken in baby food to ensure label accuracy and prevent food fraud.

Contribution

The study evaluates the reliability of dPCR using myostatin as a housekeeping gene for species quantification in commercial meat products.

Findings

Digital PCR showed fewer differences compared to Real Time PCR at the same chicken spiking level.

The genome copies ratio between mammalian and avian species could not be used as a correction factor due to increasing confidence intervals.

Using myostatin with dPCR proved reliable for verifying label compliance in meat-based products.

Abstract

Currently food fraud and authenticity of products composition are topics of great concern; ingredients quantification could allow to identify small amounts of contaminats or voluntary addition of improper components. Many molecular methods are available for species identification in foodstuffs but, for a better application, they should not be affected by the interference of other ingredients. The main purpose of this work was to verify the Real Time PCR and the Digital PCR (dPCR) quantification performances on baby food samples, specifically selected for their high miscibility to limit variability; chicken was selected as target to verify the performance of quantification of methods after having spiked the same quantity in different baby foods. The other aims were: (1) to verify a constant genome copies ratio existence between mammalian and avian species (2) to verify the dPCR performance, set up on housekeeping, to quantify mammalian and avian species in commercial products. Digital PCR showed fewer differences respect to Real Time PCR, at the same 15% w/w chicken spiking level. Despite the constant difference between mammalian and avian genome copies, in samples with the same spiking weight, the confidence intervals increasing towards the extreme values, made impossible to use genome copies ratio as a sort of correction factor between species. Finally, the dPCR system using the myostatin housekeeping gene to determine the chicken content seemed reliable to verify the labelling compliance in meat-based commercial products.

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