Vincent Baeten

Currently, many methods based on various analytical techniques are used to authenticate agro-food products. Among them, vibrational spectroscopy techniques include NIR, MIR, Raman and Terahertz techniques. They are techniques to consider when authenticity controls need to be established at the field level, at the point where products are delivered to factories or during the production process. Methods based on these techniques are indirect, rapid and do not require skilled staff. They are not confirmatory and are therefore seldom used in official control processes. A section of this chapter provides a general overview of the technology, main principles, instrumentation, sample presentation and new trends, as well as giving a brief overview of the chemometric tools used to extract chemically relevant information from the spectra. In another section of the chapter, several examples are discussed to illustrate the potential of vibrational spectroscopy in tackling authenticity challenges (e.g., the discrimination of cereal varieties), in identifying botanical origin, geographical origin and distillers’ dried grains and solubles (DDGS) production process, in the traceability and authentication of fruits and in the early detection of fraud in food/feed ingredients.

Epidemiological studies have indicated that the most likely pathway of the infection of cattle with bovine spongiform encephalopathy (BSE) is feed-borne contamination with animal proteins. The enforcement of the ban on meat and bone meal in feed for farmed animals, including the “species-to-species” ban, is considered an important measure to prevent the spread of BSE. This review summarises more than ten years of work on species identification, quantification, comparison with optical microscopy, combination with polymerase chain reaction and detection based on chemometric decision rules and discriminant models. In the first part of the review, a summary is given of existing methods for the detection, identification and quantification of processed by-products of animal origin. In the second part, the possibilities offered by the near infrared microscopy technique for detecting, identifying and quantifying processed by-products of animal origin is reviewed. Work needed on enforcing the feed ban in terms of both routine and official control measures is also discussed.

The aim of this work is to show new advances in the analytical methods developed in the frame of the ban of processed animal by-products in compound feed that is currently applied within the European Union. With this aim, studies to develop a quantitative near infrared microscopy (NIRM) approach have been undertaken in order to fulfil future requirements of European legislation like the introduction of tolerance levels that would require for official control purposes the availability of specific quantitative methods. The capabilities of the NIRM method have been improved; no sample preparation is required and the acquisition parameters are optimised. Both the gross and the fine fractions of the samples are considered; the reflexion mode was used to analyse the gross raw fraction and the transmission mode was chosen to analyse the fine raw fraction. Parameters for reflexion analyses were already fixed in our previous studies while those of transmission mode have been determined in the present study. Because particles are too small, it is difficult to mark them; spectra were collected using the mapping technique. Quantitative analyses have been carried out for different percentages of adulteration (0.5, 1, 2 and 5%). Results were depending on the particle size distribution of the feed and of the fish meal which led to experimental values of adulteration varying between 0.13–0.92%, 0.93–3.7%, 2.42–5.83% and 1.95–9.39% for theoretical percentages of adulteration equal to 0.5, 1, 2 and 5%, respectively. The established protocol with the key parameters proposed has to be considered for the development of an accurate method of quantification.

In the last decade, Raman spectroscopy has gained in maturity as a valuable technique for lipid analysis. The technique is non‐destructive, does not need sample presentation thereby allowing use in in situ and on‐line analysis, and is relatively cost effective. Recent studies have demonstrated the potential of Raman spectroscopy for determining and quantifying different parameters and properties of lipids, and for following oxidative deterioration.

This paper presents a framework for developing and validating a near infrared (NIR) hyperspectral imaging method as a standard protocol accepted by regulatory authorities. The focus is on detecting processed animal proteins (PAPs) in feedstuffs. Studies aimed at determining the performance characteristics and robustness of the protocol are presented. Various criteria and tests were used to assess the limit of detection, the repeatability and the risk of cross-contamination and to validate the NIR hyperspectral imaging method for detecting PAPs in compound feed. This protocol has been fully tested and validated though different studies in line with International Standard ISO 17025 and it is essential in order to transfer the method to other laboratories and introduce this technology to official control at the laboratory level.

Near-infrared microscopy (NIRM) has been proved to be a powerful tool for the detection of banned meat and bone meal (MBM) in feed. The identification of MBM traces and its ability to differentiate animal from vegetable feed ingredients is based on the evaluation of near-infrared spectra obtained from individual particles present in the sample. This evaluation is supported by appropriate decision rules for the absorbances at specific wavelengths. Here we show that the method and the corresponding decision rules can be successfully transferred from the laboratory which constructed the decision rules to two independent laboratories that were not involved in the calibration process of the method. The analytical results from blind feed samples containing MBM (positive samples) and feed samples without MBM (negative samples) revealed a very good agreement between the three laboratories, thus demonstrating the transferability of the method.

Since the bovine spongiform encephalopathy (BSE) crisis, the use of animal proteins in animal feed has been prohibited. From October 2003, the European Union (EU) adopted Regulation (EC) no. 1774/2002 governing animal by-products (ABPs), which seeks to address the possible risks inherent in recycling potential infectivity due to the absence of barriers within species and to exclude the cannibalism which may be induced by intra-species recycling. There is an urgent need to develop fast and reliable methods for identification of low-level ABP origins. In this study, near infrared (NIR) microscopy was used to identify different classes of ABPs. Samples of fish meals ( n = 10) and meals of land-animal origin ( n = 50) were ground, sedimented and analysed using an Auto Image Microscope connected to a Fourier transform near infrared spectrometer (FT-NIR). Sediment fraction particles were spread on a Spectralon plate, presented to the NIR microscope and scanned in the 1112–2500 nm region. The support vector machine (SVM) algorithm was used to construct models to identify class origin. Models correctly classified 100% of the samples in the calibration set and between 95 and 95.5% in the validation set. The results demonstrated the potential of FT-NIR microscopy as a rapid method for distinguishing between fish and land-animal particles.

The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is still a challenge with the current official standards. FT-Raman and FT-MIR spectroscopies have been used to determine the level of detection of the presence of hazelnut oil in olive oil. Spectroscopic analysis has been made not only with the entire oil but also with its unsaponifiable matter. Univariate and multivariate statistical models have been designed with this objective. This study shows that a complete discrimination between olive and hazelnut oils is possible and that adulteration can be detected if the presence of hazelnut oil in olive oil is >8% and if the blends are of Turkish olive and hazelnut oils. The limit of detection is higher when the blends are of edible oils from diverse geographical origins. Keywords: Olive oil; hazelnut oil; FT-Raman; FT-MIR; chemometrics

In this paper we present an alternative method for detection of meat and bone meal (MBM) in feedstuffs by near-infrared microscopic (NIRM) analysis of the particles in the sediment fraction (dense fraction (d >1.62) from dichloroethylene) of compound feeds. To apply this method the particles of the sediment fraction are spread on a sample holder and presented to the NIR microscope. By using the pointer of the microscope the infrared beam is focussed on each particle and the NIR spectrum (1112–2500 nm) is collected. This method can be used to detect the presence of MBM at concentrations as low as 0.05% mass fraction. When results from the NIRM method were compared with the classical microscopic method, a coefficient of determination (R²) of 0.87 was obtained. The results of this study demonstrated that this method could be proposed as a complementary tool for the detection of banned MBM in feedstuffs by reinforcement of the monitoring of feeds.