Cradle-to-Gate Life Cycle Assessment of Pasteurised Liquid Egg: Environmental Hotspots, Co-Product Allocation Effects and Implications for Sustainable Egg Supply Chains

Liquid egg is a key intermediate for the bakery, confectionery, and food service sectors, yet the environmental profile of egg breaking and pasteurisation is far less documented than that of shell egg farming. This study aimed to quantify the cradle-to-gate impacts of pasteurised liquid egg, to locate the hotspots a processor can manage, and to test the sensitivity of the results to co-product handling and to the upstream egg dataset. An attributional life cycle assessment (ISO 14040/14044) was performed for a functional unit of 1 kg of pasteurised liquid egg at the factory gate. Four foreground unit processes, factory processing, cleaning-in-place, packaging, and transport, were modelled in openLCA with Ecoinvent, Agribalyse, and agri-food background datasets; eggshell was treated as an economic co-product; and impacts were characterised with the CML-IA baseline method. The cradle-to-gate global warming impact was 2.62 kg CO2 eq per kg, with 93% of it from the shell egg supply; the farm stage dominated every category (78–99.9%) because feed cultivation, manure management and pullet rearing drive the egg burden, while refrigerated distribution was the largest on-site contributor (44% of processing emissions). Co-product handling moved the result only between 2.28 and 2.62 kg CO2 eq, whereas published farm-gate egg footprints raised it to 4.1–5.9 kg CO2 eq per kg. The sustainability of liquid egg is thus decided upstream, in feed sourcing, hen productivity, and manure management; processors can reduce their share through cold-chain optimisation, heat recovery, and cleaning efficiency, and policy should prioritise national egg and electricity inventories, transparent allocation rules and circular valorisation of eggshell and spent hens.