Is this a myth about bug eggs in flour?

Cindy Leigh

PJ, I came across this statement on another BB. Can you comment?

All flour has weevil eggs in it, right from the flour mill. Freezing it will kill the eggs before they hatch, so no buggy flour. If you're not able to freeze it or keep it in the freezer, a couple of whole dried bay leaves will almost always keep the eggs from hatching. We freeze in common Zip Lock bags and keep some bread flours in the freezer for 6 months or longer without a problem.

It's not a question of keeping the bugs out, just keeping the eggs from hatching.

badge posted by: Cindy Leigh on February 21, 2011 at 7:48 am in General discussions
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reply by: PaddyL on February 21, 2011 at 9:45 am

Not all flour has weevil eggs in it; these are usually picked up if the flour has to sit in a store where there are weevils for any length of time. Bay leaves may not stop eggs from hatching, but they will keep the flying insects away.

reply by: pjh on February 21, 2011 at 12:46 pm

Cindy, Paddy's right - I don't think you can make the statement that all flour has weevil eggs. We're surrounded by flour here in the King Arthur test kitchen, and have never experienced a full-blown infestation - flour where eggs have obviously hatched. That said, bugs are SO pervasive around flour, even in the cleanest of mills, that the government allows a certain amount of "ground bugs" in flour. Every good miller tries as hard as possible to keep this number very low, obviously.

It's true that bay leaves discourage insects, though they don't keep any eggs from hatching.

As for whether freezing kills weevil eggs - I've surveyed the test kitchen, and the answer is, we don't think so, but we may be wrong.

reply by: Mike Nolan on February 21, 2011 at 12:53 pm
Mike Nolan

Any bag of flour you get COULD have insect eggs in it. It's also true that most eggs will not hatch, so a bag of flour may not ever get weevils in it, even if it is several years old.

It is also far more likely that any infestation happened after the flour left the miller, during transport or while sitting in warehouses, in the store, or in your kitchen.

There are a number of things you can do to control or limit flour weevil infestations, including making sure your flour canisters are sealed, cleaning spilled flour, cereal and other food up quickly (including cleaning out your kitchen drawers periodically), and using pheromone-based insect traps, like these:

Freezing flour is supposed to help kill any eggs in it, but I'm not convinced the freezing/thawing doesn't negatively affect the quality of the flour, so most of my flour doesn't go in the freezer any more.

Birdseed seems to be a common source for insects, so we try to keep it in the garage or workshop rather than in the house.

reply by: Cindy Leigh on February 21, 2011 at 1:56 pm
Cindy Leigh

Thanks for the.... Uh...... Info I'd rather not think about!!
I thought the guy who posted that quote was all wet. Glad I never find any "aliens" in my flour!

reply by: Mike Nolan on February 21, 2011 at 3:40 pm
Mike Nolan

If you read a detailed microscopic analysis of most foods, you'd lose your appetite!

reply by: beachdee on February 21, 2011 at 4:34 pm

Reminds of what the University Extension fellow told me on the phone last summer as we discussed a new "baddie" here in the NW... he said that if the fruitfly laid its egg in the (for example) raspberry, and the egg hatched into a little fruitfly maggot, and the only place that maggot had ever been, was in the raspberry, and that was all it had ever eaten... then what's the problem with a little extra raspberry-fattened protein? Of course, that philosophy doesn't help the commercial berry growers who's produce has to pass stringent inspections before sold on the market. So, I suppose one could pass that concept on to a flour weevil? Altho personally I'd rather not be involved with that experiment!

He also said, as Mike did, that we'd probably all be pretty amazed to find out how much "incidental protein" we ingest every day. hmmm good thing I already ate lunch ... !

reply by: Cindy Leigh on February 21, 2011 at 4:49 pm
Cindy Leigh

Lol as an organic gardener, I understand completely! I've learned to wash at least twice.

reply by: carolinorygun on February 22, 2011 at 11:45 am

Weevils are health-oriented - they prefer the more nutritious whole grains.

You can kill any weevils (rice or granary) by heating flour in the oven to 129 degrees for 30 minutes or by freezing flour to
-1 degree for five hours. It takes a lot of cold to kill a weevil.

(Information from Washington State Extension service.)


reply by: Mike Nolan on February 22, 2011 at 1:30 pm
Mike Nolan

That may kill the weevils but what about any unhatched eggs?

reply by: carolinorygun on February 23, 2011 at 1:10 am

I do know the oven treatment takes care of the eggs. I don't know about freezing, but then the oven is more reliable for home purposes anyway.

I was also told by an extension agent that putting flours and grains in airtight canisters (Tupperware-type food storage) is a good measure because if eggs hatch they crawl to the surface and then smother. As they have a relatively short life-cycle, they don't have to be sealed up long to get your answer.

If you don't see any bugs, you know the flour is "clean." If you do see bugs, they'll be on the top of the food. They'll be contained, preventing dispersal, and they'll die. Ugly but practical advice.

Here's a good Extension document on the various types:


reply by: islandwoman on March 20, 2011 at 3:03 pm

Bugs and bug eggs are NO myth. I've been cooking since age 10 and through the years have opened my crawling flour bags to a big surprise! Freezing couldn't hurt the flour - I'm going to try it as soon as I have room in my freezer.

You're probably sick of replies to this post so I'll sign off.

Island Woman

reply by: islandwoman on March 20, 2011 at 3:07 pm

It's funny, I'm originally from Californai where I suffered the little buggers more than once. Here, after 22 years of living in the NW, I don't have the flour weevil problem anymore. Until recently, I wasn't using the flour any faster either. They say we eat a lot of critters in our cereals too.

Still, I'm going to start freezing my flour. I seem to remember "things" getting out of the tupperware containers. ARGH, gross and creepy!

Island Woman

reply by: islandwoman on March 20, 2011 at 3:09 pm

flour weevils are NOT microscopic. Therefore, they gross us out!

reply by: KitchenBarbarian aka Zen on March 20, 2011 at 5:44 pm
KitchenBarbarian aka Zen

GROUND UP weevils are microscopic.

And it shouldn't "gross you out". All food contains microscopic amounts of things we'd rather not think about.

reply by: KitchenBarbarian aka Zen on March 20, 2011 at 5:51 pm
KitchenBarbarian aka Zen

Maybe freezing won't kill weevil eggs, I guess I've not done a microscopic examination before and after to tell.

But when I was a kid, flour weevils were pretty much a given - sooner or later you WOULD get weevils, even if you were buying Gold Medal from the grocery store.

This stopped entirely when we started freezing flour. After we started freezing flour, I never ever again found weevily flour.

reply by: frick on March 21, 2011 at 5:54 pm

I don't freeze anything except whole grain flours, and even usually keep those in the frig. I haven't had a weevil in my house in years though I do clean shelves frequently. I put everything in Cambro as soon as it is opened. I have more than a dozen flours and meals and no problem at all. I used to find little round beetles in red pepper but those have disappeared also. It totally confuses me.

I have never been accused of being a hysterical conspiratorialist (is that a word?) but I have concluded that a lot of spices and probably some grain products are now being irradiated to kill eggs.

Some of you with a background in food production at the raw materials level could chime in on this.

I did find a jar of walnuts entirely consumed by those nasty moths last year. Now, most nuts get frozen if not used fairly soon.

reply by: karenbrat1 on March 20, 2011 at 11:50 pm

When I was growing up, we were not exactly well to do. When the flour got weevils in it, we sifted it through a fine sieve and used it anyway!

reply by: --jej on March 21, 2011 at 1:19 pm

I think I posted this info on the old BC, so some of you may want to ignore it, presumably.

We lived in India for DH's work in '65 (where everyone from 'first world countries' were expected to have a cook and about four or five other employees). We could bring only so much with us in terms of food, and as 'common folk' working there for private industry, we had no access to the U.S. government-run supplies there for armed services and government employees. So flour was one of the local items we bought.

Well, let me tell you how much fun it was to be 'between cooks' and dependent upon local flour. I was soon sick of trying to pick out those little weevils and promptly let it be known that we needed a new cook. A fellow who had worked for a Canadian lady who was just leaving her post was sent over, and he knew just what to do.

Maya Ram whipped up his thickening for the potato soup for DH and not a single little weevil could you find! Why?? Because as soon as it was heated and brought to the boil, they were dead and floating on top, whereupon he simply skimmed them off.
Unfortunately, I think he poured it through my lovely sifter, which ended up stuck with a lot of dried flour stuff in it and had to be tossed.

I never ate the soup, btw, so that is why it was for DH.

Don't even ask me what he did to get rid of them for cake, rolls, etc. I never knew, and probably don't want to know.

reply by: frick on March 21, 2011 at 5:59 pm

Don't read this if you are squeamish. Once, in Mexico we bought bollilos. As I was eating one as soon as we hopped back in the car, it became apparent the bakery was infested with (won't name it). Never again.

reply by: Mike Nolan on March 22, 2011 at 6:06 am
Mike Nolan

Frick, I think our imaginations may be worse than your reality. :-)

Our local paper publishes restaurant inspection reports from time to time, I can think of a few restaurants in town I won't ever go to based on those reports. (And if you watch shows like Restaurant Impossible on TV, you might wonder why some of those places haven't been shut down by the health inspectors.)

reply by: KitchenBarbarian aka Zen on March 22, 2011 at 9:29 am
KitchenBarbarian aka Zen

My ex was from India, and when we visited after we got married, he was so excited to show me all his favorite restaurants and street vendors - except he'd been gone about 6 years and when he got a look at some of these place, he turned green. *I* was less bothered by it than he was, LOL!

Food was pretty good anyway and no, I didn't get any kind of Raja's revenge while we were there, LOL!

reply by: elisabethberthasavage on March 22, 2011 at 11:41 am

PJ - I have worked with Phil on our Consumer's line so some of this information has passed over my desk. What I know is the presence of rice or granary weevils inside the home usually indicates there is infested whole grain or seeds (this includes beans, popcorn, garden seeds, Indian corn...). Control requires locating and eliminating the infested whole grain. If someone wanted to save the grain, they can control the weevils by heat or cold. Heating grain to 140 degrees Fahrenheit for 15 minutes or freezing at 0 degrees F for 3 days will kill all stages of weevils in the grain. Elisabeth

reply by: MangoChutney - Sandra Too on April 27, 2011 at 8:39 pm
MangoChutney - Sandra Too

Flour weevil eggs look a lot like flour. I used to find them in the folds of the external flaps on grocery store flour bags. Even if there were no weevils in the flour when it left the factory, eggs could get laid on the outside from infested flour that was stored in the same grocery-chain warehouse. These could then hatch and eat their way into the uninfested bags.

I have bought well-known brand name boxes of rice at the grocery store that had rice moth eggs in them, too. I never saw the eggs on those, but the rice that was stored in a closed metal can hatched out rice moths.

I have had Velveeta cheese boxes infested with some kind of insect also, which boggles the mind. They didn't eat the cheese but they made lace out of the foil wrapper which left the cheese exposed to mold. The Velveeta was on clearance sale, which means it had been sitting in the store for quite some time.

You really have to watch dry goods from large grocery chains.

reply by: sandra Alicante on April 28, 2011 at 2:20 am
sandra Alicante

Has anyone got a fondness for fresh figs? If so, don't do a search on figs and wasps....

I have only twice had a (known) infestation of nasty flour critters, fortunately isolated quickly because I am so often using flour and spotted it fast.
Did have a yucky infestation of something else though. Bought some dried catnip on line from the States, because of what it was, thankfully it was put in an airtight container and not kept with the food stuffs. Went to give the cats a treat on day and ugggh! Creepies all over it!