Pumping but you work outside? How to keep parts clean?

Hi folks!

I am an environmental scientist and I travel to job sites a few times a week to delineate wetlands. I will be going back shortly, and will need to pump!

I am planning on using my pump with a car adapter for power, and have an insulated lunchbox with good ice packs. I’ll start my day with a sanitized pump and containers for the expressed milk, but it will be several hours before I get anywhere with soap and water to wash the parts.

Anyone have any ideas on how I can keep the flanges/cups clean and safe to use? I’ll need to pump more than once throughout the day, and replacement parts are expensive, especially when I would need multiple sets to get me through the day. Is it enough to just rinse them in between use? I should also add that I work in a hot and humid climate so I’m concerned about bacterial growth.

Thanks in advance!