Over the past few decades, with the growth of science and technology and increasing the variety of products, demand for higher quality products has also been increasing. Although this has raised the welfare of societies, it has increased the cost of companies. In today’s business market, products quality plays an important role to attain social welfare Current study investigates a two-level supply chain including a manufacturer and a packaging company which produce substitutable products. These substitutable products are different in terms of quality.
