TITLE:
Validation of Two Real-Time PCR Approaches for the Relative Quantitation of Pork and Horse DNA in Food Samples
AUTHORS:
Malcolm Burns, Gavin Nixon
KEYWORDS:
Food Authenticity, Food Adulteration, Meat Speciation, Meat Quantitation, Real-Time PCR
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.13 No.4,
April
24,
2022
ABSTRACT: Two real-time PCR methods for the relative
quantitation of DNA from meat species in food samples are described: these
methods are applicable for horse in processed beef meat products, and pork in
raw/processed beef meat products. Test samples were prepared using raw meat
admixtures or processed horse/pork in beef food products made to an industry-standard
recipe. The methods were subjected to single laboratory method validation,
evaluating the performance characteristics of specificity, PCR efficiency and
r-squared (r2), Limit of Detection (LOD), Limit of Quantitation
(LOQ), and precision and trueness. A limited UK-based inter-laboratory trial of
the two methods was completed involving four participating laboratories. Full
statistical analysis of the data qualified the applicability of the methods for
accurate and sensitive trace-level analysis. The methods were deemed fit for
purpose for reproducibly distinguishing between adventitious contamination at
0.1% (w/w), the level for further enforcement action at 1% (w/w), and a level
representative of deliberate economically motivated adulteration (10% (w/w)).
The data provided evidence that the precision of the two methods was applicable
for qualitative and quantitative detection at topically important levels of
adulteration. This work has added significant value to the current state of the
art in quantitative determination of topical meat species adulteration,
allowing analysts to distinguish between adventitious contamination and
deliberate adulteration. The resulting methods described in this paper can
easily be deployed and used by analytical laboratories for controls and
due-diligence testing based on standard laboratory equipment.