A fluid product reservoir, for a dispensing system, is made of a container having walls that include an aperture formed at one end thereof. A reservoir cap seals the aperture from exposure to the atmosphere. A pump integrated into the reservoir cap allows fluid product to be dispensed from the dispensing system. A closed venting mechanism is included and incorporates one or more air channels that direct ambient air into a bladder positioned internal to the fluid product reservoir. The expansion of the bladder functions to displace fluid pumped from the reservoir thereby equalizing pressure while maintaining a sanitary seal of the fluid reservoir.