A comparison of the nutritional quality and sensory properties of commercial milk with different labeled production systems

In the current marketplace, different quality seals exist for commercial milk to support producers in (a) sustaining the additional costs related to the practice of unconventional and less intensive production systems and (b) endorsing consumers requirements and expectations toward superior milk quality, including inner (healthiness, taste) and external (sustainability, origin, production method, animal welfare) quality features. The aim of this research was to verify the nutritional and sensorial properties of commercial milk collected on the retail chain in the plain area of Lombardia (Italy). Four different types of retail milk were considered, including conventional ‘High Quality’ fresh milk (HQ), fresh milk labelled as ‘Mountain Product’ (MM), conventional milk with ‘Extended Shelf Life’ (ESL), and STG-certified Haymilk (HM). One sample for each type of whole milk was collected weekly during March, May, July, and September 2022, for a total of 80 samples (20 per type). Fatty acids (FAs) were quantified by gas chromatography. Milk sensory profile was assessed according to ISO 13299:2010 recommendation. Comparisons among groups were performed by means of parametric and non-parametric statistics. Results showed significant differences among the different labels for the content of many FAs that are biomarkers of origin and/or functional compounds. Particularly, HM was evidenced as the quality seal associated with the most favourable FAs profile, represented by the highest content of branched chain fatty acids (BCFA, 79.11mg/100mL), rumenic acid (RA, 35.83mg/100mL) and the lowest n-6/n-3 ratio (3.46), followed by MM (69.98mg BCFA/100mL milk; 16.92mg RA/100mL milk; n-6/n-3 ratio equal to 5.46) and the two conventional types of milk, HQ and ESL (52.71–59.23mg BCFA/100mL milk; 14.36–15.07mg RA/100mL milk; n-6/n3 ratio equal to 7.31–7.56) (p < 0.001). No significant association with the quality mark was evidenced for the sensory attributes, with the exception of aroma intensity, which showed a lower score for MM (5.03) if compared to HM, HQ, and ESL milk (6.32, 6.94, and 7.47, respectively) (p < 0.001). The outcomes obtained in this research provided useful knowledge for all the stakeholders involved in the milk supply chain, from producers to consumers, supporting the existence of a relationship between the claims on milk label and its nutritional quality and indicating a superior quality of commercial milk obtained by certified production systems.