Ambient air filtering at a cannery - can blower

Good morning - I am looking for any information on what type of air filter is typically used for filtering ambient air that is blowing out food packaging cans prior to filling (point of use - not compressed air). 

Our plant is under SQF, which leaves it up to the plant to choose our air monitor air program and what our acceptable levels of air contaminant are based on internal risk assessment. 

We monitor our ambient air annually at a minimum using air plating using a standard set by an outside consultant.  We monitor for mold, and if we get >10 cfu we will resample and investigate, but there is not much we can do except talk to employees about keeping roll up doors shut. As a cannery we do not have a filtered air system in our general plant.  We are using a MERV 8 filter on the air that blows into the cans prior to fill. This has been in place prior to my working here, I am adding justification to our air monitoring plan. 

We do not have any issues or complaints that can be traced back to contaminated air in causing a food safety or quality issue, but I would like to be able to explain to an auditor why we are doing what we are doing, unless there is a better way out there.  

Thanks in advance for any thoughts!  

Hi, Does the air blowing into can ionized?

No, it is not ionized. It is ambient air.