Green Lean Six Sigma for Waste and Emissions Reduction in Small-Scale Pasteurized Milk Production

The pasteurized milk industry faces major efficiency and sustainability challenges due to high energy use, production waste, and product defects. This study analyzes production waste, evaluates process performance, quantifies environmental impacts, and develops Green Lean Six Sigma (GLSS)-based improvements in a small dairy processor in Indonesia. Data was collected through 30 days of observation, time studies, expert questionnaires, and records of electricity and Liquid Petroleum Gas (LPG) consumption across bottle and cup packaging lines. The main types of production waste identified include waiting, defects, residual product, packaging-material waste, unnecessary motion, and excessive power use during mixing and sealing. Implementation of the Define–Measure– Analyze–Improve (DMAI) framework reduced production time to 387.11 minutes for bottles and 337.26 minutes for cups. Defect rates reached 3.9% and 6.1%, corresponding to sigma levels of 3.56 and 3.38. CO₂ emissions from electricity and LPG decreased significantly, especially in the energy-intensive stages. Process improvements were achieved through layout redesign, enhanced supervision, energy optimization, and a Kanban-based pull system. The integrated GLSS model effectively improved efficiency, product quality, and environmental performance, providing a structured foundation for continuous improvement in small-scale food industries.