本研究探討個案公司如何使用六標準差手法，改善即食食品生產之不良率。依據DMAIC步驟循序漸進地進行專案改善；由歷史數據分析，定義出關鍵品質特性為成品生菌數。利用統計分析，篩選顯著影響變數之因子；藉由實驗設計找出最佳參數組合，並驗證改善效果。將參數標準化，修訂相關作業標準。結果顯示生菌數超標問題獲得改善，並降低失敗成本的支出。

The aim of the research is focusing on the outcome of the decrease of defective rate during the period of producing ready-to-eat food with the method of five phases of Six Sigma, and to improve the quality step by step based on DMAIC. Through the data analysis in the past, critical-to-quality factor was identified and converted into the viable count in final product, and then the most significant factors affecting the viable count were selected by a variety of statistical analysis. In the meanwhile, design of experiments was implemented to find out optimal parameter of the factors and the effectiveness of the modification was confirmed. Finally, the final parameters were standardized and the relevant standard operating procedures were amended. The result shows that the problem of the viable count has been improved and the expenses on failure costs can effectively cut down.