In recent years, digital transformation (DX) is getting more and more important even in small and medium companies, facing various difficulties such as labor shortage, lack of capital and information. Especially, in food industries, business owners are challenging innovations for both quality and quantity of products. In this paper, we have approached an improvement of productivity at a company with three manufacturing lines as a case study. The study was executed in using a combination of OODA loop with IoT based on HACCP rules. It is not aimed to reduce employees by IoT, instead it is proposed a way of improving the value of companies with it. We found that not only OODA loop would contribute to enhance in productivity of manufacturing lines when it was with IoT monitored or shared data in real time, also it improved in communication between employees suggested Pareto improvement was possible.