It's best to make sure you are safe- doing your own pedicure is best but if you go to a salon make sure you do not have any open sores or cuts; do not shave, use hair removal creams, or wax your legs during the 24 hours before receiving treatment in a foot spa. There are many organisms that grow in water such as bacteria.
Ask the spa/salon if the pumice and tools they are using are new or disinfected. Know how the salon cleans and disinfects foot spas. Ask salon workers how the foot spas are maintained and how often. A foot spa should be disinfected between each customer, and nightly. The disinfectant needs to work for the full time listed on its label, typically 10 minutes, depending on the type of disinfectant. Proper cleaning and disinfection is the best way to reduce infection.
Another way to avoid this is to do your own and not let anyone else use your tools. A product you can easily buy online is called The Foot System For Smoother Feet by Now Care Products. They give away free samples and their website is footpedicure.net/zencart
The last tip is that if you go to a salon or spa bring your own pumice stone and or other tools you will need. It is always better to be on the safe side and prevention is the key. Take care of your feet and stay healthy.