The residuality of Aquapy depends on application rate and concentration it can be applied at rates that have no residuality after 24 hours or upto 2 weeks after application. This may or may not be of benefit to you based on the nature of the treatment ongoing, your best to discuss the full aims of the treatment with you contractor who has recommended the treatment as it may be necessary to leave the residue in non food contact areas so the treatment may have full effect. This may mean isolating the area and not wet cleaning for a given period of time. Ensure all areas are fully cleaned prior to treatment for best effect and easier clean up post treatment.
Prior to treatment ensure all food surfaces are covered to minimise contamination risk form the outset. Post treatment and in accordance with the direction in relation to residual time given by your contractor you should be able to wash down as per your standard protocol paying extra attention to direct and indirect food contact areas.
You can review label data here ahead of your treatment: http://www.environme...uaPy label.ashx
If you do not feel comfortable with areas being treated don't allow it to happen and discuss alternatives with your contractor. If worried about residue take samples of rinse water and have tested as per Mohammad's suggestion
You are unlikely to run into issues if responsibly applied and clean up managed.