Life cycle environmental assessment of yogurt production and consumption in the USA

Abstract Text: The innovation Center for U. S. Dairy commissioned and jointly conducted a life cycle assessment (LCA) of the yogurt supply chain focused on defining potential environmental impacts with the University of Arkansas. The system boundaries for this study include milk production, yogurt processing, filling and packaging, retail, and finally through consumption of the yogurt and including disposal of the packaging material.  Estimated impacts in various unit processes (milk production, processing, packaging, transport, retail, and consumption) including product losses at each stage are reported and discussed. 

The functional unit is 1 kg of yogurt products consumed by U.S. consumer as sold at retail, for the year 2013. LCA data were analyzed using stochastic methods (Monte Carlo simulation) to quantify and characterize uncertainty. The impact categories used in the evaluation include:

•             Climate change 

•             Photochemical oxidant formation

•             Cumulative energy demand         

•             Freshwater eutrophication

•             Freshwater depletion     

•             Water Eutrophication     

•             Human toxicity, and

•             Marine eutrophication   

•             Ecosystems

•             Ecotoxicity

Here, the environmental profile is defined as the comprehensive set of inventory and impact assessment results.  The report also provides interpretation and evaluation of the results to help identify the potential risks and opportunities in the yogurt production value chain. 

The overall cradle-to-grave GHG emissions for set, stirred, and non-traditional Greek yogurt as sold at retail were found to be 6.03, 4.98, and 7.65 kg CO₂e per kg of yogurt consumed, respectively. Using a simulated traditional Greek yogurt plant for production LCI, the cradle-to-grave greenhouse gas emission were estimated to be 8.92 kg CO₂e per kilogram consumed. 

In the cradle-to-grave assessment, production of milk is the dominant contributor to most environmental impacts, and thus ongoing industry efforts to improve milk production will lead to improvements in the yogurt manufacturing sector as well. In the farm-gate-to-retail-gateanalysis, yogurt transport was the single largest GHG emission contributor followed by ingredients, electricity, and packaging materials. The results suggest that careful optimization of the transport distances and the selection of transport refrigeration system using low-GWP refrigerants could reduce environmental impacts.

Keywords: Yogurt, LCA, Environmental Impact