Bovine beta casein polymorphism and environmental sustainability of cheese production: The case of Grana Padano PDO and mozzarella cheese

Several genetic variants of ?-casein have been identified but A1 and A2 are the most common. Bovine ?-casein variants may play an important role on cheese yield and quality, besides milk production and composition, and, thereby, affect environmental sustainability of cheese production processes. The aim of the study was to investigate the possible effect on environmental sustainability of cheese production, related to bovine ?-casein polymorphism. A Life Cycle Assessment (LCA) was performed, considering Grana Padano PDO and mozzarella cheese, made with either A1A1, A1A2 or A2A2 ?-casein milk and using economic and dry matter allocation methods for cheese and co-products. Additionally to characterization, normalization and weighting (endpoints method), were also performed. Results on the environmental impact of 1 kg of packaged cheese showed that, among the ?-casein genetic variants, A1A1 seemed to be the most impactful, only due to the lower individual daily milk production of cows belonging to A1A1 group, compared to the cows belonging to A1A2 and A2A2 groups, i.e. 29.6, 37.1 and 34.6 kg of fat and protein corrected milk (FPCM) day cow, respectively. Allocation method strongly affected the impacts per kg of cheese product and, consequently, of co-products. The normalization allowed to understand the relative importance of different impact categories and the result obtained indicated that the notable impact categories of the cheese industry were natural land transformation, aquatic eutrophication and terrestrial acidification. Results of the weighting highlighted that greater damage was given to the ecosystem quality, followed by human health and, finally, resource scarcity. Overall, biggest differences were detected for the two cheeses, rather than for the ?-casein genetic variants and the differences in environmental sustainability of cheese made with A1A1, A1A2 and A2A2 milk were mainly due to the different cow milk production, rather than cheese yield. Therefore considering only the technological properties useful for cheese making the selection of milk with A2A2 ?-casein may be not so convenient. Normalization and weighting results allow to identify the most impactful categories and so can help decision-makers to determine where to prioritize efforts aimed at reducing cheese environmental impact.