Gate-to-Gate Life Cycle Assessment of Small-Scale Yogurt Production in Bogor, Indonesia

Abstract

This study presents a gate-to-gate Life Cycle Assessment (LCA) of small-scale yogurt production in Bogor, Indonesia, covering the production stage from raw material input to final packaged yogurt. The foreground system boundary excludes distribution, consumption, and end-of-life stages, while purchased raw materials (particularly raw milk) are represented using cradle-to-gate secondary datasets that inherently embed upstream agricultural burdens; this scope distinction is clarified explicitly in this revision. The assessment follows ISO 14040 and ISO 14044 standards and was conducted using openLCA software with the ReCiPe 2016 Midpoint (H) method, with a functional unit of 29.158 kg of packaged yogurt (one production batch). The Life Cycle Inventory (LCI) results show that the primary inputs include cow milk (27.184 kg), skimmed milk powder (2.000 kg), sugar (1.000 kg), microbial starter (0.030 kg), water (2.000 kg), and packaging materials (0.624 kg), with wastewater (2.150 kg) and organic residue (1.530 kg) as system outputs. The Life Cycle Impact Assessment (LCIA) results indicate that Global Warming Potential (GWP) is the most significant impact category, reaching 76.513 kg CO₂ eq per batch, equivalent to approximately 2.624 kg CO₂ eq per kg of packaged yogurt, followed by acidification (0.524 kg SO₂ eq), human toxicity (0.259 kg 1,4-DCB eq), freshwater eutrophication (0.131 kg P eq), and ozone depletion (5.51×10⁻⁴ kg CFC-11 eq). The hotspot analysis reveals that raw milk sourcing is the dominant contributor to environmental impacts across most categories, reflecting the influence of the cradle-to-gate background data embedded in the milk input. In conclusion, improving raw material sourcing, optimizing water and energy consumption, and enhancing waste management are essential strategies to improve the environmental performance of small-scale yogurt production systems.