The trick is to simply exhaust this air from the fans directly to the exterior of your home.
Can you use bathroom fan in kitchen.
This would be the minimum ventilation.
This can lead to wood rot mold and mildew.
Depending on your usage you might consider a slightly larger fan to make sure you have enough power to clear the room.
Bathroom and kitchen exhaust fans also can transmit large volumes of moist humid air into the attic or other confined spaces.
A bath fan just won t cut it.
You cannot by code and should not by practical reasoning share exhaust venting between a kitchen exhaust and a bathroom exhaust fan.
The general rule is 1 cfm per square foot of space with standard 8 foot ceilings.
That would be 960 cf assuming 8 ft ceilings.
You say the kitchen is 120 sf but you need to take in to account the height.
As a general rule bathroom fans are not suitable for use in the kitchen as many have no filter inside them.
An alternate approach is to use a ducted range hood or downdraft exhaust and a bathroom ventilation fan to exhaust the general odors and moisture in the kitchen.