Rapid and non-destructive analysis of apricot fruit quality using FT-near-infrared spectroscopy

A non-destructive optical method based on near-infrared spectroscopy has been used for the evaluation of apricot fruit quality. Diffuse reflectance measurements (800–2500 nm), physical, physiological and biochemical measurements were performed individually on 877 apricot fruits from eight contrasted cultivars harvested at different ripening stages. Relationships between spectral wavelengths and quality attributes were evaluated by application of chemometric techniques based on partial least squares (PLS) on fruit set divided randomly into two groups: 598 fruits for calibration and 279 for validation. Good prediction performance was obtained for soluble solids and titratable acidity with correlation coefficients of 0.92 and 0.89 respectively and root mean square errors of prediction of 0.98% Brix and 3.62 meq 100 g⁻¹ FW respectively. For the other quality traits such as firmness, ethylene, individual sugars and organic acids, the prediction models were not satisfactorily accurate due to the high error of calibration and prediction.     

New approach for the quantification of processed animal proteins in feed using light microscopy

A revision of European Union's total feed ban on animal proteins in feed will need robust quantification methods, especially for control analyses, if tolerance levels are to be introduced, as for fishmeal in ruminant feed. In 2006, a study conducted by the Community Reference Laboratory for Animal Proteins in feedstuffs (CRL-AP) demonstrated the deficiency of the official quantification method based on light microscopy. The study concluded that the method had to be revised. This paper puts forward an improved quantification method based on three elements: (1) the preparation of permanent slides with an optical adhesive preserving all morphological markers of bones necessary for accurate identification and precision counting; (2) the use of a counting grid eyepiece reticle; and (3) new definitions for correction factors for the estimated portions of animal particles in the sediment. This revised quantification method was tested on feeds adulterated at different levels with bovine meat and bone meal (MBM) and fishmeal, and it proved to be effortless to apply. The results obtained were very close to the expected values of contamination levels for both types of adulteration (MBM or fishmeal). Calculated values were not only replicable, but also reproducible. The advantages of the new approach, including the benefits of the optical adhesive used for permanent slide mounting and the experimental conditions that need to be met to implement the new method correctly, are discussed.     

Determination of aflatoxin M1 in milk by triple quadrupole liquid chromatography-tandem mass spectrometry

A sensitive and reliable method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an electrospray-positive ionization method was developed for the determination of aflatoxin M₁ in milk. This method includes simple extraction of the sample with acetonitrile by ultrasonic, separation on an MGIII-C₁₈ column using 0.01% formic acid buffer/acetonitrile (60 : 40, v/v) as mobile phase, and MS/MS detection using multiple reaction-monitoring mode. Average recoveries of aflatoxin M₁ from spiked samples at concentrations of 0.02 and 1 ng ml^?1 ranged from 77% to 94%, with a 6% relative standard deviation. The limit of detection and limit of quantification were 0.006 and 0.02 ng ml^?1, respectively. The standard curve was linear between 0.02 and 20.0 ng ml^?1. The recommended method is simple, rapid, specific and reliable for the routine monitoring of aflatoxin M₁ in milk.     

Development of an accelerated solvent extraction,ultrasonic derivatisation LC‐MS/MS method for the determination of the marker residues of nitrofurans in freshwater fish

A rapid method using accelerated solvent extraction (ASE) and ultrasound enhanced derivatisation has been developed for the quantitative determination of metabolites of nitrofurans, namely 3‐amino‐2‐oxalidinone (AOZ), 5‐morpholinomethyl‐3‐amino‐2‐oxalidinone (AMOZ), 1‐amino‐hydantoin (AHD) and semicarbazide (SEM), in muscle and skin of carp and finless eel. The target analytes were extracted using ASE, ultrasonic derivatisation for 1?h and then purified by solid phase extraction. Averaged decision limits (CCα) and detection capability (CCβ) of the method were in the range of 0.07–0.13 and 0.31–0.49?µg?kg^?1 in carp and finless eel, respectively. The accuracy in terms of recovery was in the range 77.2–97.4%. The simplified and traditional methods were compared with incurred residue samples. The simplified method reduced the derivatisation time and has been applied to the determination of nitrofurans residues in fish.     

A general method to validate breeding value prediction software

The validity of national genetic evaluations depends on the quality of input data, on the model of analysis, and on the correctness of genetic evaluation software. A general strategy was developed to validate national breeding value prediction software: performances from a real data file were replaced with simulated ones, created from simulated fixed and random effects and residuals in such a way that BLUP estimates from the evaluation software must be equal to the simulated effects. This approach was implemented for a multiple-trait model and a random regression test-day model. An example was presented on test-day observations analyzed with a random regression animal model including a lactation curve described as a sum of fixed polynomial regression and fixed spline regression on days in milk, and with genetic and permanent environmental effects modeled by using Legendre polynomials of order 2. Residuals had heterogeneous variances, and phantom parent groups were included. This method can be easily extended to other linear models. The comparison of genetic evaluation results with simulated true effects is used to demonstrate the great efficiency and usefulness of the proposed method.     

Short communication: Validation of somatic cell score–associated loci identified in a genome-wide association study in German Holstein cattle

Recently, we identified 6 genomic loci affecting daughter yield deviations (DYD) for somatic cell score (SCS) in a genome-wide association study (GWAS) performed with German Holstein bulls. In the current study, we tested if these loci were associated with SCS in cows using their own performance data. The study was performed with 1,412 German Holstein cows, of which 483 were daughters of 71 bulls that had been used in the GWAS. We tested 10 single nucleotide polymorphisms (SNP) representing 6 genomic regions that were associated with DYD for SCS in bulls. All tested SNP were significant in cows. Seven of them, located on Bos taurus autosomes (BTA) 6, 13, and 19, had the same direction of effect as those previously reported in the bull population. The most significant associations were detected on BTA6 and BTA19, accounting for 1.8% of the total genetic variance. The major allele of the 2 SNP on BTA6 and the minor allele of the 2 SNP on BTA19 were favorable for lower SCS. The differences between the homozygous genotype classes were up to 15,000 cells/mL. The verification of SNP associated with SCS in this study provides further evidence for the functional role of the linked genomic regions for immune response and contributes to identification of causative mutations. In particular, SNP with minor frequency of the favorable allele possess high potential to reduce SCS in German Holstein cattle by selection.     

Determination of pyrethroids in chicken egg samples: development and validation of a confirmatory analytical method by gas chromatography/mass spectrometry

The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques.     

Optimisation of an analytical method and results from the inter-laboratory comparison of the migration of regulated substances from food packaging into the new mandatory European Union simulant for dry foodstuffs

This paper presents the outcome of the development, optimisation and validation at European Union level of an analytical method for using poly(2,6-diphenyl phenylene oxide – PPPO), which is stipulated in Regulation (EU) No. 10/2011, as food simulant E for testing specific migration from plastics into dry foodstuffs. Two methods for fortifying respectively PPPO and a low-density polyethylene (LDPE) film with surrogate substances that are relevant to food contact were developed. A protocol for cleaning the PPPO and an efficient analytical method were developed for the quantification of butylhydroxytoluene (BHT), benzophenone (BP), diisobutylphthalate (DiBP), bis(2-ethylhexyl) adipate (DEHA) and 1,2-cyclohexanedicarboxylic acid, diisononyl ester (DINCH) from PPPO. A protocol for a migration test from plastics using small migration cells was also developed. The method was validated by an inter-laboratory comparison (ILC) with 16 national reference laboratories for food contact materials in the European Union. This allowed for the first time data to be obtained on the precision and laboratory performance of both migration and quantification. The results showed that the validation ILC was successful even when taking into account the complexity of the exercise. The results showed that the method performance was 7–9% repeatability standard deviation (rSD) for most substances (regardless of concentration), with 12% rSD for the high level of BHT and for DiBP at very low levels. The reproducibility standard deviation results for the 16 European Union laboratories were in the range of 20–30% for the quantification from PPPO (for the three levels of concentrations of the five substances) and 15–40% from migration experiments from the fortified plastic at 60°C for 10 days and subsequent quantification. Considering the lack of data previously available in the literature, this work has demonstrated that the validation of a method is possible both for migration from a film and for quantification into a corresponding simulant for specific migration.     

Predictive Microbiology Models and Operational Readiness

A diverse field of predictive microbiology models has emerged in the past 30 years and has advanced our understanding of microbial behavior in foods. As most of published models have for objective to provide operationally relevant information to decision makers, predictive microbiology models have now found their place within both the academic, and the food industrial communities.Given the importance of these models to food safety, the decision makers are in need of evidence-based advices in order to assess confidence in the predictions provided by models they use. The objectives of this work were (i) to review current approaches in predictive microbiology used to build, verify and validate models, and (ii) to propose a categorization scheme that would tend to define a model's viability for use in an operational setting.     

Development and validation of a UPLC–ELSD method for fast simultaneous determination of five bile acid derivatives in Calculus Bovis and its medicinal preparations

A reverse phase ultra-performance liquid chromatography coupled with evaporative light scattering detection (UPLC–ELSD) method was successfully established for simultaneous determination of five bile acid derivatives in Calculus Bovis and its medicinal preparations using a Waters Acquity UPLC T3 C₁₈ column (2.1 × 50 mm, 1.8 μm) with gradient elution of 0.2% aqueous formic acid and acetonitrile. The influence of liquid flow-rate and column temperature, gas flow-rate and drift tube temperature on resolution was investigated to get the optimized parameters and conditions. This method was validated according to the regulatory guidelines with respect to precision, accuracy and linearity. Under optimum conditions, the five analytes were baseline separated in 11 min with detection and quantification limits ranged in 3.0–6.0 ng and 6.0–18.0 ng, respectively, which provided about a twofold reduction in analysis time and good efficiency and sensitivity by comparing a conventional high performance liquid chromatography (HPLC) method.