Carbon footprint of PDO cheeses: Grana Padano and Gorgonzola

The aim of the study was to evaluate the carbon footprint of two PDO Italian cheeses: Grana Padano and Gorgonzola. Grana Padano is a hard long ripening cheese, composed by 65% of dry matter, consisting of 38% protein and 24% fat. Gorgonzola cheese, instead, is a blue soft cheese with a short ripening period composed by 58.6% of dry matter (28.7% fat and 21.4% protein). The productive process of Grana Padano was studied at a cheese factory that in 2015 processed 86,165,255 L of milk, producing 183,611 cheese wheels, with an average yield of 7.6%. For Gorgonzola, a cheese factory was studied; in 2015, it processed 12,542,552 L of milk, producing 126,910 Gorgonzola wheels with an average cheese yield of 12.5%. The Carbon footprint was quantified using Life Cycle Assessment (LCA) method, carried out through a “cradle to cheese factory gate” point of view. All data considered were referred to 2015 and the functional unit was 1 kg of cheese. Gas emissions of milk production, at farm level, were calculated using IPCC (2009) and EEA (2009) equations, then impact categories were evaluated using IPCC (2007) method. Both economic and dry matter allocations were applied. Assuming the economic allocation and considering the whole productive process, Global Warming Potential (GWP) was 16.9 kg CO2 eq. per kg of Grana Padano, higher than GWP of Gorgonzola that resulted 10.7 kg CO2 eq. Using the DM allocation, the unitary GWP resulted 10.3 kg CO2 eq. for Grana Padano and 6.0 kg CO2 eq. for Gorgonzola. These different values are mainly due to the lower cheese yield of Grana Padano in comparison to Gorgonzola, which implies a higher unitary value of environmental impact. The milk production at farm was the most important contribute of the GWP using an economic allocation at cheese factory (excluding ripening and packaging): 95.6% for Grana Padano and 90.3% for Gorgonzola. The phase of milk processing slightly contributed to GWP of both cheese but some differences were observed: a higher use of cleaning products (0.54% vs 0.02% of GWP) for the sanitization of the plant and use of electricity, principally for air conditioning of cheese factory (5.79% vs 1.64% of GWP) for Gorgonzola and Grana Padano processing respectively. The outcomes of this study highlight how, due to the multiple products produced at the dairy plants, the choice of the allocation method deeply affects of the environmental burdens of cheeses.