It is alleged Richard Griffin, 64, and William Hammersley, 79, who died in 2012, were exposed to harmful levels of Legionella bacteria from a heated spa display.
JTF Wholesale Limited has pleaded not guilty to two counts of corporate manslaughter.
A trial is expected next year.
The firm also denied four counts of health and safety breaches during a hearing at Stafford Crown Court on Monday.
It is accused of failing to take reasonable care to prevent or control the men's exposure to harmful levels of bacteria at its store in the Fenton area of Stoke.
JTF is also accused of failing to ensure the safety of employees and customers under the Health and Safety at Work Act and failing to prevent or adequately control exposure to substances hazardous to health.
A firm has denied causing the deaths of two men alleged to have caught Legionnaires' disease from a hot tub at one of its stores.