What you see: A moldy strawberry or two in a pack that otherwise looks fine.
What it is: Mold (duh).
Eat or toss: Toss the moldy one(s). If it was just one or two berries, the others should still be OK, but start with a taste test and consume the rest soon.
Just one moldy berry
If one strawberry is moldy, does that mean that your entire carton of sweet, summery goodness needs to be dumped?
In a word, no.
But let’s add some details and caveats.
You shouldn’t eat mold
First off, you don’t want to eat mold. Some molds contain toxins that could make you sick now, or in the long term. Airborne mold spores can trigger respiratory allergies. And if your food is moldy, that means the mold, and possibly some other microbes, is hard at work breaking it down so it simply won’t taste right.
The USDA’s guidance on mold is that moldy soft and high-moisture foods should be tossed in their entirety. Trimming at least an inch is recommended for hard, dense, low-moisture foods.
If it’s just one moldy berry, toss it and take a close look at the rest
So, back to that one moldy berry. Here’s the thing: multiple scientist sources I consulted said it’s usually OK to just toss the moldy berry and eat the rest.
Can you guarantee that those berries haven’t come into contact with mold spores? No, in fact it’s likely that they have, given that they’ve been rooming with a moldy berry. But mold spores are everywhere and touch a lot of our foods. We’re most concerned with avoiding berries with actively growing mold.
Also worth considering: while the molds most likely to contaminate strawberries are devastating for fruit growers, and while it’s not a good idea to eat them, they generally aren’t human health threats. The most common mold found in strawberries is a character called Botrytis cinerea. It’s grayish white and fluffy. You can find beauty shots here and here.
Botrytis cinerea, which ravages lots and lots of crops, also ranks second on the Top 10 Fungal Pathogens in Molecular Plant Pathology, so you know it’s serious.
But while its spores are allergens that could make you sneeze or give you a runny nose, it’s highly unlikely to make you truly ill. In fact, Botrytis cinerea is also known as “noble rot” because some wine growers deliberately let it grow on their grapes. Yep, you read that right! Botrytis is actually prized for its ability to concentrate sugars and flavors in grapes used to make sweet wines. (But no, the moldy strawberry in your carton won’t be extra delicious so don’t try it. Here at EatOrToss we discourage amateur mold identification and the consumption of any uninvited mold.)
And, get this: you’re probably already eating Botrytis spores. The fungus sometimes first digs into the strawberry plant (and loads of other crops) at the flowering stage and just hangs out quietly, waiting for the fruit to soften and sweeten before it starts spinning the sinister fuzz.
Dangerous molds produce toxins that can make you ill. But Botrytis isn’t known to generate toxins and, in any event, USDA reports that in molds that do present health threats, the poisons are usually found in and around the mold’s threads, not the spores.
Just to cover all our bases, I did find one documented case of a healthy man suffering from a Botrytis infection in his lungs. The background section of the paper notes that “botrytis species are well known fungal pathogens of various plants but have not been reported as human pathogens except as allergenic precipitants of asthma and hypersensitivity pneumonitis.”
Other types of mold grow on strawberries too
While Botrytis cinerea is the most common strawberry mold, other molds can also cause the heart-shaped fruits to rot and go fluffy. Whatever the invader is, the fruit won’t taste good and could also be hosting some bacteria, so you definitely don’t want to eat it.
But as long as its fruity neighbors still look pristine, they should be fine to eat. For now. Eat them fast!
- Exposure to the airborne mould Botrytis and its health effects. December 2009. Annals of agricultural and environmental medicine: AAEM 16(2):183-96. Claudia Juergensen and Anne Mette Madsen (National Research Centre for the Working Environment).
- Postharvest Disease of Selected Commodities. Noel F. Sommer, Robert J. Fortlage, Donald C. Edwards. Chapter 18 of Postharvest Technology of Horticultural Crops. 2002. Editor: Adel A. Kader. University of California Division of Agriculture and Natural Resources.
- Botrytis Fruit Rot / Gray Mold on Strawberry. Frank Louws. Department Head, Horticultural Science. North Carolina State University Extension.
- Botrytis Fruit Rot. Agriculture: Strawberry Pest Management Guidelines. Statewide Integrated Pest Management Program. University of California Agriculture and Natural Resources.
- Strawberry IPM- Gray Mold. Angela Madeiras, Sonia Schloemann. Center for Agriculture, Food, and the Environment. UMass Extension Fruit Program. University of Massachusetts at Amherst.
- Hashimoto S, Tanaka E, Ueyama M, et al. A case report of pulmonary Botrytis sp. infection in an apparently healthy individual. BMC Infect Dis. 2019;19(1):684. Published 2019 Aug 2. doi:10.1186/s12879-019-4319-2
- Postharvest decay of strawberry fruit: Etiology, epidemiology, and disease management. Journal of Berry Research 6 (2016) 47–63 DOI:10.3233/JBR-150113 IOS Press 47 E. Feliziani and G. Romanazzi∗ Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Via Brecce Bianche, Ancona, Italy
- One Moldy Berry. Episode 139. Risky or Not. Hosts: Don Schaffner (Rutgers University) and Ben Chapman (North Carolina State University).
- Mould Sensitisation among Bakers and Farmers with Work-related Respiratory Symptoms. Industrial Health. 2013. Marta WISZNIEWSKA1 *, Diana TYMOSZUK1 , Ewa NOWAKOWSKA-ŚWIRTA1 , Cezary PAŁCZYŃSKI1 and Jolanta WALUSIAK-SKORUPA1 1 Department of Occupational Diseases, Nofer Institute of Occupational Medicine, Poland.
- Cecilia N. Nunes, Ph.D. Associate Professor. Food Quality Laboratory. Department of Cell Biology, Microbiology and Molecular Biology. University of South Florida
- Beth Mitcham. Interim Director. Postharvest Technology Center, University of California-Davis.