Study Shows NIRS Can Accurately Authenticate Acorn-Fed Iberian Pigs on Farm

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Researchers in Spain have demonstrated that near-infrared (NIR) spectroscopy can reliably authenticate the feeding regime of purebred Iberian pigs while the animals are still alive, offering a potential new tool to strengthen traceability and reduce fraud in one of Europe’s most tightly regulated meat sectors.¹

In a study published in Food Control, a team led by Alberto Ortiz at the Centre of Scientific and Technological Research of Extremadura evaluated whether NIR spectroscopy could distinguish between pigs finished exclusively on acorns and those receiving varying levels of supplementary feed during the final fattening stage in the Dehesa ecosystem.¹ The work addresses a long-standing challenge in the Iberian pig industry, where premium prices depend on verified feeding practices that are difficult to monitor in real time.

The Dehesa ecosystem contains high biodiversity.^2,3 It comprises of livestock, pasture, and trees that is designed to promote more sustainable agriculture practices.² In the Dehesa, one could see flora, which include cork and holm oaks and animals such as the Iberian lynx.³

In their study, the research team monitored 167 purebred Iberian pigs across three feeding strategies. These feeding strategies were acorn-fed animals (40), partially supplemented pigs (83), and fully supplemented pigs (44).¹ After the finishing period, the NIR spectra were collected in vivo from each animal.¹ These data were used to develop a classification model by employing partial least squares–discriminant analysis (PLS-DA). External validation demonstrated that this new model achieved accuracy levels above 90% in external validation, with a Matthews Correlation Coefficient of 0.77, indicating strong discrimination despite the similarities among feeding regimes and shared access to natural resources.¹

According to the authors, the results confirm that NIR spectroscopy can detect subtle differences in tissue composition linked to diet, particularly changes in lipid profiles and antioxidant content of subcutaneous fat, which are key markers influenced by acorn consumption during the finishing stage. Unlike conventional laboratory-based authentication methods, NIR spectroscopy requires no sample preparation, is non-destructive, and delivers rapid results.¹

This study comes at a time when the increasing availability of compact and portable NIR spectroscopy devices is changing how spectroscopic analysis is conducted. This technological trend is allowing for more analysis to be done on-site. In the context of this study, this trend could potentially help inspectors in authenticating animals directly in the Dehesa rather than relying solely on post-slaughter analyses or documentation audits.¹

“The development of compact and portable prototypes makes this technology highly suitable for on-farm measurements under real field conditions, making it applicable to the authentication challenge addressed in this study,” the authors wrote in their study.¹

References

1. Ortiz, A.; García-Gudiño, J.; León, L. et al. In Vivo Authentication of Acorn-fed Purebred Iberian Pigs in Dehesa Ecosystem Using Near-Infrared Spectroscopy. Food Cont. 2026, 184, 112002. DOI: 10.1016/j.foodcont.2026.112002
2. Onoszko, K.; Gomez, F. J. R.; Lazzaro, L. et al. Diversity Patterns of Herbaceous Community in Environmental Gradients of dehesa Ecosystems. Glob. Ecol. Conserv. 2024, 54, e03162. DOI: 10.1016/j.gecco.2024.e03162
3. Museo del Jamon, The Dehesa: Spain’s Natural Treasure. Museo del Jamon. Available at: https://www.museodeljamon.com/en/the-dehesa/ (accessed 2026-02-10).