In the US, the minimum disinfecting and sampling frequencies are defined in 40 CFR 141, Subpart X, Table B-1.
Frequency can vary by airline choice, but at a minimum it may conform to the following:
DISINFECT: At least 4 times per year, AND, SAMPLE: At least once per year.
-OR-
DISINFECT: At least 3 times per year, AND, SAMPLE: At least twice per year.
-OR-
DISINFECT: At least 2 times per year, AND, SAMPLE: At least four times per year.
-OR-
DISINFECT: At least 1 time per year, AND, SAMPLE: At least twelve times per year.
https://www.ecfr.gov/cgi-bin/text-id...41_main_02.tpl