DNA-based verification that gelatin-containing foods and cosmetics do not contain pork products has always been a challenge due to DNA damage and destruction during gelatin production.
In this study (open access) the authors report that – by careful optimisation of conditions – they could successfully apply a “traditional” PCR test to the problem.
They describe DNA extraction, post-isolation DNA analysis, annealing temperature and primer concentration optimization, specificity assay, amplification efficiency trial, sensitivity test, repeatability examination, and marketed sample analysis.
They report that the developed method demonstrated good specificity under optimized conditions. It achieved a good amplification efficiency of 101.2% with an R² of 0.994. The real-time PCR technique had a limit of detection of 1,316 pg in the sensitivity examination and a coefficient of variation of 0.81% in the repeatability testing.
They tested 10 retail samples (five facial mask cosmetics, food additive gelatin powder, two marshmallow products, and two gummy candy products), reporting that all of the samples displayed no amplification and were thus considered not to contain porcine DNA, consistent with the manufacturers’ labels.
The authors conclude that their real-time PCR method meets the validation criteria for qualitative analysis, including specificity, amplification efficiency, sensitivity, and repeatability.
