Abstract: [Objective] To investigate the effect of stirring process in dairy product processing on the dissolved oxygen content of milk. [Method] During the dairy processing,the dissolved oxygen content of milk directly affects the quality of the final product. Different liquid levels and stirring speeds in the tanks may result in variations in the dissolved oxygen content. This study focused on milk samples from the high,medium,and low liquid levels of the raw milk storage tank and the filling buffer tank,and measured and compared the dissolved oxygen content in the sample under different stirring rates. [Result] During milk storage,if the rotational speed remains constant in the raw milk storage tank,the dissolved oxygen content of milk at the high liquid level is（8.74±0.18）ppm,at the medium liquid level is（9.10±0.13）ppm,and at the low liquid level is（9.55±0.42）ppm. The dissolved oxygen content significantly increases as the liquid level decreases;if the rotational speed decreases as the liquid level decreases in the filling buffer tank,the dissolved oxygen content at the high liquid level is（8.81±0.11）ppm,at the medium liquid level is（8.80±0.17）ppm,and at the low liquid level is（8.79±0.13）ppm. There is no significant change in the dissolved oxygen content as the liquid level decreases. [Conclusion] The data from this experiment can provide a theoretical foundations and practical guidance for optimizing the production of dairy products to reduce dissolved oxygen content.

Key words: dissolved oxygen content, stirring, dairy product processing, milk, stability