Rita Boerrigter-Eenling

Verification of fresh grass feeding, pasture grazing and organic farming by cows farm milk fatty acid profile.

The present study investigated the use of fatty acid (FA) profiling in combination with chemometric modelling to verify claims for cow milk in terms of fresh grass feeding, pasture grazing and organic/biodynamic farming. The FA profile was determined for 113 tank milk samples collected in the Netherlands from 30 farms over four different months, and used to develop classification models based on the PLS-DA algorithm. Milk from cows with daily rations of fresh grass could be successfully distinguished from milk from cows with no fresh grass in their diet. Milk from cows at pasture could easily be distinguished from milk from stabled cows without fresh grass in the diet, but the correct prediction of milk from stabled cows fed fresh grass indoors proved difficult. The FA profile of organic/biodynamic milk was different compared to conventional milk but an unequivocal discrimination was not possible either in summer or in winter.

Compositional Signatures of Conventional, Free Range, and Organic Pork Meat Using Fingerprint Techniques

Consumers’ interest in the way meat is produced is increasing in Europe. The resulting free range and organic meat products retail at a higher price, but are difficult to differentiate from their counterparts. To ascertain authenticity and prevent fraud, relevant markers need to be identified and new analytical methodology developed. The objective of this pilot study was to characterize pork belly meats of different animal welfare classes by their fatty acid (Fatty Acid Methyl Ester—FAME), non-volatile compound (electrospray ionization-tandem mass spectrometry—ESI-MS/MS), and volatile compound (proton-transfer-reaction mass spectrometry—PTR-MS) fingerprints. Well-defined pork belly meat samples (13 conventional, 15 free range, and 13 organic) originating from the Netherlands were subjected to analysis. Fingerprints appeared to be specific for the three categories, and resulted in 100%, 95.3%, and 95.3% correct identity predictions of training set samples for FAME, ESI-MS/MS, and PTR-MS respectively and slightly lower scores for the validation set. Organic meat was also well discriminated from the other two categories with 100% success rates for the training set for all three analytical approaches. Ten out of 25 FAs showed significant differences in abundance between organic meat and the other categories, free range meat differed significantly for 6 out of the 25 FAs. Overall, FAME fingerprinting presented highest discrimination power.

Characterization of Retail Conventional, Organic, and Grass Full-Fat Butters by Their Fat Contents, Free Fatty Acid Contents, and Triglyceride and Fatty Acid Profiling

In the Netherlands, butter is produced from milk originating from three different production systems: conventional, organic, and grass-fed cows. The aim of the current study was to characterize these types of butters, and pinpoint distinct compositional differences. Retail conventional (n = 28), organic (n = 14), and grass (n = 12) full-fat butters were collected during the winter and summer seasons. Samples were analyzed for their fat content, free fatty acid (FFA) content, and triglyceride (TG) and fatty acid (FA) profiles. The fat content was significantly lower in conventional butters than in organic butters and the FFA content was significantly lower in conventional butters compared with grass butters. Also, organic butters differed significantly from their conventional counterparts with regard to their TG and FA profiles. The TG profiles of the organic and grass butters did not differ significantly. The FA profiles of grass butters were less distinct, since only a few FAs differed significantly from conventional (six FAs) and organic (eight FAs) butters.

New approaches towards discrimination of fresh/chilled and frozen/thawed chicken breasts by HADH activity determination: Customized slope fitting and chemometrics

Fresh/chilled chicken breasts retail at a higher price than their frozen/thawed counterparts. Verification of the fresh/thawed status of chicken meat is determined by measuring β-hydroxyacyl-Coenzyme A-hydrogenase (HADH) activity present in meat intra-cellular liquids spectrophotometrically. However, considerable numbers of reference samples are required for the current arithmetic method, adding to laboratory costs. Therefore, two alternative mathematical approaches which do not require such reference samples were developed and evaluated: curve fitting and multivariate classification. The approaches were developed using 55 fresh/thawed fillet samples. The performance of the methods was examined by an independent validation set which consisted of 16 samples. Finally, the approach was tested in practice in a market study. With the exception of two minor false classifications, both newly proposed methods performed equally well as the classical method. All three methods were able to identify two apparent fraudulent cases in the market study. Therefore, the experiments showed that the costs of HADH measurements can be reduced by adapting alternative mathematics.