Star San for mildew on wooden cutting board?

April 27, 2019 10:25 AM

Can I use Star San to kill the black mildew on a wooden cutting board? If so, how; and if not, what else can I use?

I have Star San for cleaning my homebrewing gear, and I love it.

Can I use it on the black mildew that makes an otherwise-nice cutting board kind of gross? How long would I soak it, and at what concentration?

If this isn't the correct approach, what should I do instead?

THANK YOU

posted by wenestvedt to Home & Garden (15 answers total)

I wouldn’t soak a wood cutting board because it’s likely to split or warp. I assume the mildew is in/on the wood and not on any sort of protective coat. At most, I’d put on a thin spray, let sit for 10 minutes, wipe, and repeat as needed.

Use this once you’re done (probably multiple apply-wait-wipe-buff cycles the first time) and reapply whenever water is able to soak into the wood.
posted by supercres at 10:29 AM on April 27, 2019 [1 favorite]

Best answer: I wouldn't ever soak a wooden cutting board. If a cutting board has developed black mildew, I would just use soap and water, scrub as much as possible, let is dry, re-sand, possibly re-plane if necessary, and then make sure to oil it, and keep it oiled in the future.

Star san is great, but not in this application. Moisture is the enemy of a cutting board.
posted by furnace.heart at 10:31 AM on April 27, 2019 [3 favorites]

Best answer: Have you tried vinegar?
posted by pinochiette at 11:30 AM on April 27, 2019 [2 favorites]

Couple of days of exposure for each side outdoors in direct sunlight works well too.
posted by flabdablet at 12:15 PM on April 27, 2019 [2 favorites]

Best answer: Kosher salt and vinegar or lemon juice is a common method - the grit of the salt helps to scrub everything out of any small gaps or cuts. Combine a generous amount of salt (don't be shy, it's cheap!) in a couple tablespoons of liquid and scrub it all over the board with little circular motions and plenty of elbow grease. Once the entire surface is thoroughly scoured, let it sit until the salt dries out enough to be brushed off. Depending on how much mildew there is, you may need to go through that process one or two more times.

If that doesn't work, you may need to use a little diluted bleach as a last resort.

Once the board is clean let it completely dry - like, wait a few hours at minimum or overnight; setting it out in direct sunlight will also help speed that up. Then work some plain old cheap food-grade mineral oil (most grocery stores carry it) into the top with your hands and let it soak in for 5-10 minutes. If the board absorbs all the oil, which is a good possibility if you've never treated it before, work some more oil in and wait another 5-10 minutes. You might even need to do it a third time before there's oil left to wipe off the surface. Then do the same to the other surface and all the sides.

You may already know this, but: don't soak a cutting board or leave it wet, and don't stick it in the dishwasher. Wipe up any wet spills as soon as you're done using it. If you really need to wash it, don't immerse it in a sinkful of water; set it on the top edge of the sink, drizzle some dish soap on it and clean it with a damp sponge/scrubber. Then rinse it off and stand it somewhere upright to completely dry. At least the first few times you do that, you may need to re-apply some mineral oil (again, after it's dry) - that's a judgement call, but the worst that will happen if you re-apply the oil is that the board won't soak up any more so you'll just have to wipe it off.
posted by Greg_Ace at 1:42 PM on April 27, 2019 [1 favorite]

Bleach is excellent at killing mold & mildew, I'd use a 1:4 bleach: water solution and scrub well with a plastic scrubby on a sponge, then wipe with a similar solution of vinegar to neutralize the bleach.
posted by theora55 at 1:55 PM on April 27, 2019

Best answer: Bleach can't penetrate into the wood to kill the mold roots. Vinegar can kill mold and penetrate into the wood, so it's going to be a more effective cleaner.
posted by DetriusXii at 4:19 PM on April 27, 2019 [1 favorite]

Bleach can't penetrate into the wood to kill the mold roots.

I didn't realize that, but there's a lot of information online backing that up. #TIL.
posted by Greg_Ace at 4:53 PM on April 27, 2019 [1 favorite]

Star San is a phosphoric acid-based foaming sanitizer. Based on the suggestions for vinegar, and my homebrewing experience, I'd start with mechanical cleaning, then spray with your regular Star San concentration that you’d use to sanitize anything else.

Supposedly you don’t have to rinse, but I always do. I’d maybe spray it and let it work its way in, and let it air dry. (Then rinse it later.)
posted by Huffy Puffy at 4:54 PM on April 27, 2019 [1 favorite]

What are people cutting on cutting boards that they aren’t needing to be washed after?
posted by Iteki at 3:28 AM on April 28, 2019

Wood cutting boards are good at killing bacteria (although I don't know if edge-grain boards perform like end-grain boards). I don't use my wooden cutting board for raw meat (I put a nylon board down on top of it for that), but I do everything else - mainly veggies, cheese, and bread - on it, and 9 times out of 10 it doesn't need anything more that a quick wipe with a damp cloth or sponge. A couple times a year I do the salt-and-vinegar thing I described upthread for good measure. I've had this board for 10 years and kept reasonable care of it, and it looks as good as the day I bought it (though somewhat darker). I have yet to suffer any ill effects from not washing it after every use.
posted by Greg_Ace at 10:17 AM on April 28, 2019 [1 favorite]

Rather than messing around with all the chemicals I'd probably just try sanding it off and re-oiling the board.
posted by aspersioncast at 2:40 PM on April 29, 2019 [1 favorite]

rinse it off and stand it somewhere upright to completely dry

Better to sit it in a dishrack at an angle so that any drainage drips all go to one corner and fall off from there. Standing a wooden board up on end encourages drainage to wick into a pool between the end of the board and whatever you're standing it on, and if it's a glued board this will eventually cause enough differential swelling to split the joints.
posted by flabdablet at 6:13 AM on April 30, 2019 [1 favorite]

Response by poster: Eventually the folks at Five Star Chemical got back to me and agreed with you all that Star San isn't the tool for this.

*sigh* Back to the (black, moldy) drawing board....
posted by wenestvedt at 7:40 AM on May 22, 2019

Something else you can try is heat. Get the board nice and oily to make it somewhat moisture resistant, then use it to cover a pot of water simmering on the stove until it feels warm on the upper side as well. That should mean that the lower side, the one exposed directly to the steam, has been collecting and condensing steam at about boiling point for some minutes and will be pretty much sterilized.

You will need to move the board around several times to make sure of properly scalding the entire surface.
posted by flabdablet at 7:55 AM on May 22, 2019