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GROUP 5, SESSION B: FOOD PRODUCTS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
149. Comprehensive life cycle assessment for cheese and whey
products in the U.S.
Greg Thoma 1,* , Darin Nutter 2 , Rick Ulrich 1 , Dae-Soo Kim 1 , Greg Norris 3 , Franco Milani 4 , Dean Sommer 4
1 Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR, USA, 2
Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA, 3 Walton College of
Business, University of Arkansas, Fayetteville, AR, USA, 4 Department of Food Science, University of Wisconsin
– Madison, Madison, WI, USA, * Corresponding author. E-mail: gthoma@uark.edu
A comprehensive life cycle assessment (LCA) has been carried out to determine a benchmark for the environmental
impacts associated with cheddar and mozzarella cheese consumption in the United States. This
includes specifically product loss at various stages of the supply chain, as well as consumer transport and
storage of products. The scope of this study was a cradle-to-grave assessment with particular emphasis on the
unit operations of typical cheese processing plants.
A functional unit of 1 metric ton of cheese consumed (dry solids basis), or 1 metric ton of whey delivered
(dry basis) was adopted. The ecoinvent database was used for ‘upstream’ unit processes. Operational data
from 17 cheese manufacturing plants representing 24% of mozzarella production and 35% of cheddar production
in the US. Allocation procedures follow the ISO 14044 hierarchy. System separation was used when
sufficient information was available, primarily as plant-specific engineering estimates. Incoming raw milk,
cream or dry milk solids are allocated using a milk solids mass balance. Revenue-based allocation was used
for remaining in-plant processes.
Life cycle impact assessment was conducted using the ReCiPe and USEtox frameworks. Greenhouse gas
(GHG) emissions are of significant interest, and on a dry milk solids basis, the carbon footprint of both cheddar
and mozzarella is approximately 13.0 metric tons CO2e (IPCC 2007 factors) per metric ton of cheese
consumed (inclusive of product loss across the supply chain). The 95% confidence interval ranges from 9 to
18 metric tons CO2e per metric ton of cheddar cheese (dry solids basis) consumed. For an average solids
content of 63.2% for cheddar as sold at retail, the cumulative GHG emissions are 8.5 kg CO2e per kg cheddar
cheese consumed, and for an average solids content of 51.4% for mozzarella, the GHG emissions are 7.3 kg
CO2e/kg consumed. Fig. 1 shows the relative contribution from different supply chain stages to both the cradle
to grave impacts and the post-farm gate impacts (that is impacts excluding milk).
This study provides a benchmark for the US cheese manufacturing industry to gauge improvement over time
and showed that energy use, especially electricity, across the supply chain is relevant to several impact categories,
including climate change, cumulative energy demand, photochemical oxidant formation, and human
toxicity (USEtox). The impacts to ecosystems (ReCiPe) are driven almost exclusively by agricultural land
occupation (63%) while the aquatic ecotoxicity (USEtox) impacts are driven significantly by fly control pesticides
which are used in dairy operations and to lesser extent crop protection chemicals. Improvement opportunities
focused on reducing energy consumption will have broad beneficial impacts, both economic
through cost savings, as well as environmental due to the emissions reduction.
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