## 1 Introduction  
The Iberian Spanish market provides a wide variety of traditional meat and meat products, being dry-cured ones of great relevance in the Spanish diet and being also widespread among Mediterranean countries [1], mainly due to its nutritional sensory quality attributes. The quality of Iberian dry-cured products is dependent on the intrinsic characteristics of raw material (meat and fat used for its production) from which they are made, which in turn is dependent on animal production conditions. Thus, the genetic background (purebred Iberian pigs vs. Iberian crossed with Durocl), the rearing conditions (indoors vs. outdoors systems) or the type of feed received, especially in the last stage of fattening (based on natural feed vs. commercial fodder), led to a large degree of variability in the physico-chemical [2; 3; 4] and sensory attributes [5] of meat and meat products. The current Spanish Iberian Quality Standard (IQS) [6], includes the different quality categories obtained from the combinations of the above-mentioned factors. Thus, the standard officially sets out four quality levels, which are described on different commercial labels; \"_Black_\" (100% Iberian pigs that finish their fattening stage in _Montanera_-reared in the outdoors with feed-based exclusively on the _ad libitum_ consumption of acorns mainly from _Quercus__lix_ and grass-), \"_Red_\" (pigs with a minimum Iberian purity of 50%, which finish their fattening phase in _Montanera_), \"_Green_\" (pigs with a minimum Iberian purity of 50%, reared in outdoor conditions and fed with commercial fodder--mainly based on cereals and leguminous plants--without prejudice that they may also consume acorns and grass) and \"_White_\" (animals of at least 50% purebred Iberian, reared indoors and fed exclusively on commercial fodder). Nevertheless, these quality degrees are not applicable to all meat products, and exclude some such as Iberian dry-cured sausages, while others, such as fresh meat, dry cured hams, shoulders and loin, are included. Recently, [PERSON] et al. [7] highlighted the relevance of labelling in the perception of the Iberian products by consumers. Thus, the inclusion of Iberian dry-cured sausages such as _chorizo_ into the various quality degrees or commercial categories above-mentioned would provide information regarding its quality dimension, and the possibility of being commercially recognized as a classified and authenticated product by the current IQS [6]. The physico-chemical and organoleptic differences among Iberian _chorizo_ manufactured from raw meat from three commercial categories (_Black_, _Red_ and _White_) included in the current IQS [6] have been recently addressed by [PERSON] et al. [8]. So, current efforts should be focused on seeking tools to provide a quality control of Iberian _chorizo_ according to the commercial category of the raw material, thus protecting its authenticity, and supporting a labelling system that provides added value to this product as well as reliability in terms of traceability and quality control to the consumer. On the other hand, there is a trend towards the use of vacuum or modified atmosphere packaging (MAP) of sliced products as compared to the entire piece in the selling formats of meat products. In particular, the similarity to a hand-sliced product provided by MAP packaging compared to the traditional appearance of vacuum packaging, favours the tendency to choose MAP over vacuum packaging [9]. However, given their dispersion from the original whole piece, pre-sliced packaged products could be more exposed to fraudulent practices. So, quality authentication is essential in pre-sliced package selling formats. In this regard, near infrared reflectance spectroscopy (NIRS) is a fast, sensitive, and non-destructive technology that has been previously used for Iberian pig carcasses, subcutaneous fat and fresh meat classification according to the current official commercial categories by [PERSON] et al. [10].