A review of the analytical methods coupled with chemometric tools for the determination of the quality and identity of dairy products Romdhane Karoui * , Josse De Baerdemaeker Division of Mechatronics, Biostatistics and Sensors (MeBioS), Department of Biosystems, K.U. Leuven, Kasteelpark Arenberg 30, B-3001 Leuven, Belgium Received 9 February 2006; received in revised form 17 May 2006; accepted 21 May 2006 Abstract There is an increasing demand of the consumers and actors of the food industry sector to have means of measurement allowing the characterisation of raw materials or food. Dairy products (milk, ice cream, yogurt, butter, cheese, etc.) are in considerable demand, com- mand premium prices and are, therefore, vulnerable to economic adulteration. Authenticity of these products is an important issue for food processors, retailers, regulatory authorities and consumers. It is also valuable for ensuring fair competition and as a mean of pro- tecting consumers against fraud due to mislabelling. Conventional chemical methods are not able to determine the regional provenance of dairy products unambiguously. Therefore, alternative techniques such as spectroscopic techniques i.e., near infrared (NIR), mid infra- red (MIR), front face fluorescence spectroscopy (FFFS), stable isotope and nuclear magnetic resonance (NMR)-coupled with chemomet- ric tools have many potential advantages as tools for the evaluation of the identity of such products. This review article discusses the potential of destructive and non-destructive techniques for the determination of the quality and the authenticity of dairy products. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Dairy products; Identity; Quality; Spectroscopic techniques; Chemometrics 1. Introduction Product authenticity and authentication are emerging topics within the food sector (Karoui et al., 2004b). It is a major concern not only for consumers, but also for pro- ducers and distributors (Fernandez, Astier, Rock, Coulon, & Berdague ´, 2003). Indeed, regulatory authorities, food processors, retailers and consumer groups are all interested in ensuring that foods are correctly labelled. Food adulte- ration has been practiced since biblical times but has become more sophisticated in the recent past. Foods or ingredients most likely to be targets for adulteration include those which are of high-value and which undergo a number of processing steps before they appear on the market. With the European harmonisation of the agricul- tural policy and the emergence of the international mar- kets, authentication of such foodstuffs focuses more attention. This trend is the result of efforts made by regio- nal authorities, as well as producers to protect and support local productions (Karoui, Mazerolles, & Dufour, 2003). The quality of milk plays a very important role in the production of all types of cheeses, affecting both cheese yield and characteristics of the cheese (Summer et al., 2003). In regions with high production costs, agriculture needs to produce food of superior quality. The products can be labelled according to the specific conditions, which characterise their origin and the processing technology (Bosset et al., 1997). These regions can be designed for products with protected designation of origin (PDO) or protected geographical indication (PGI). Animal feeding is one of the elements that often consid- ered as important by cheese-makers (Buchin, Martin, Dupont, Bornard, & Achilleos, 1999; Bugaud, Buchin, Coulon, Hauwuy, & Dupont, 2001; Bugaud, Buchin, Noe ¨l, et al., 2001). Grass of natural highland pastures presents a 0308-8146/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2006.05.042 * Corresponding author. Tel.: +32 16321470; fax: +32 16328590. E-mail address: Romdhane.Karoui@biw.kuleuven.be (R. Karoui). www.elsevier.com/locate/foodchem Food Chemistry 102 (2007) 621–640 Food Chemistry