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Mechanically Separated Meat (MSM – sometimes called Mechanically Recovered Meat, MRM) must be declared on-pack if used in meat products.  Testing for undeclared MSM can be a significant analytical challenge.  Traditional official control methods rely on microscopy, which requires experienced interpretation and can be highly subjective. 

This paper (open access) builds upon previous published work from the same researchers to develop targeted LC-MSMS methods that are suitable for official control applications..

In contrast to a comparable study on MSM from poultry, the authors report that the use of cartilage/intervertebral disc material was not useful for porcine MSM. They therefore report a new marker protein from porcine MSM, protegrin-4, which allows the detection of 5/3/1 mm MSM. The validity of the developed assay was ensured by the investigation of 182 blinded samples. After unblinding, all samples containing 5/3/1 mm MSM and all negative control samples were correctly classified. Additional new results related to the investigation of the species specification of chicken, turkey, and pork also are presented.

They concluded that LC-MS/MS-based detection of of undeclared MSM has been successfully extended from poultry to porcine MSM. The assay was successfully transferred to a triple quadrupole LC-MS system to facilitate routine use.

Photo by Branimir Petakov on Unsplash

Differentiating gelatin species is an analytical challenge because of a lack of intact DNA.  Most speciation methods therefore target the profile of proteins.  Proteins are difficult to analyse - they are too large to measure directly by techniques such as LC-MS, without  prior breaking down, and their folded structure is also an important diagnostic parameter.  This structure is disrupted by many of the sampling and extraction procedures used in analytical method. Analysis of mixed gelatins is particularly difficult.

This method (open access) used a new approach based on the interaction of ethanol with amino acids inside a protein. Ethanol can denature globular proteins by disrupting intraprotein hydrogen bonds due to hydrophobic interactions. However, when added to solutions having proteins with considerable number of α-helices, ethanol can stabilize the protein structure and prevent aggregation. The specific effects of ethanol on protein structure and function can vary depending on the protein's composition and environment.

Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to leverage ethanol's differential effects on gelatin's amide bands for quantifying pork gelatin contamination in bovine gelatin.

The authors report that the method showed a strong linear correlation between contamination levels and amide band transmission, with detection and quantification limits of 0.85 and 2.85 mg/100 mg (pork in bovine), respectively. It effectively identified pork gelatin in halal candy, with recovery rates from 50.05 % to 103.69 %.