Even if it didn't have the option, all you'd have to do is open up the front panel and rip the beeper off the board. That's what I do to my microwaves that can't be muted.
Once upon a time I earned some major brownie points with a husband and wife by disassembling their child's electronic toy, inserting a piece of kleenex between the speaker and the grill, and reassembling it, now 30dB quieter.
Initially they suggested I just cut the wire but I figured I could do something a little easier to reverse.
Many home appliances have hidden codes you can use to adjust settings like this, including making them silent. They usually come up if you search for “Sabbath Mode”.
Initially they suggested I just cut the wire but I figured I could do something a little easier to reverse.