Excel: search cell with comma separated values ignoring spaces

I have a comma separated value in an excel cell AB, CD. There are two columns A B and C D. Now I want to search the cells to check if the comma separated value appears and if it does it would write OK or Not OK under the columns. It should ignore the spaces and while searching AB it should write OK under A B.

I tried the following formula and it works but does not ignore spaces. So it does not match AB to A B`. Any pointers?

=IF(ISNUMBER(SEARCH("AB",K2)),"OK","Not OK")