White crystals on dates are often sugar, not mold. UC Davis describes “sugar spotting” in soft date cultivars as crystallization of sugars under the skin and in the tissue; it can change texture and appearance without harming flavor. Sugar crystals tend to look dry, granular, or glassy and may feel gritty. Mold behaves more like growth: fuzzy, powdery, raised, irregular, and sometimes accompanied by musty odor or moisture. When the surface is wet, hairy, sour-smelling, or clearly moldy, discard the dates.
Dates contain enough sugar to crystallize visibly
As dates dry and age, sugars can migrate and form crystals on or beneath the skin. Soft dates rich in glucose and fructose are particularly prone to the defect described by UC Davis. Temperature changes and storage conditions can make crystallization more noticeable. The result may be pale specks, a white dusty-looking film, or gritty patches that are part of the fruit rather than a microorganism.
Sugar bloom is mainly a quality change. The date may feel firmer or slightly grainy, but it should still smell sweet and characteristic. If the crystals are internal, cutting one open can reveal pale granular areas within otherwise normal brown flesh. That pattern is different from mold filaments extending across the surface.
Mold has structure; crystals have edges and grit
Use bright light and look closely. Sugar tends to form tiny angular crystals or a dry crust that sits close to the skin. Mold is more likely to look fuzzy, feathery, or cottony and may spread in uneven colonies. Color can overlap—some molds are pale—so texture and odor matter more than “white versus not white.”
Do not sniff a visibly moldy date closely. USDA guidance advises avoiding direct sniffing of moldy foods because spores can irritate the respiratory system. If several dates in a moist package show fuzzy growth, discard the affected product rather than washing or brushing the mold away.
Sour or alcoholic odor points away from harmless sugar
UC Davis notes that dates with higher moisture can undergo yeast fermentation and become sour. A package that smells like vinegar, alcohol, or fermentation should therefore not be explained away as simple crystallization. Wet stickiness that is new, bubbling, or liquid collecting in the package also makes microbial spoilage more plausible.
Natural dates are sticky because they contain concentrated sugars, so stickiness alone is not enough. Compare the fruit with how it normally feels. Dry gritty crystals plus a sweet smell are reassuring; wet slime, fuzzy growth, or a sharp off odor are not. In uncertain cases involving visible growth, discarding is inexpensive compared with trying to identify a colony at home.
Cool, dry storage slows both quality loss and spoilage
Keep dates tightly covered and follow package instructions. Cooler storage slows browning, fermentation, and other quality changes, and helps protect the fruit from moisture pickup and insects. For long storage, many producers recommend refrigeration or freezing depending on the product.
The quick distinction is practical: crystals are dry and gritty, while mold grows in irregular fuzzy patches. Sugar spotting can make a date unattractive without making it rotten. Once white material comes with musty smell, dampness, sourness, or visible filaments, treat it as spoilage and discard the affected dates.
If you want a simple comparison, cut one date through the white area. Sugar crystals often continue into the flesh as pale granular deposits and remain hard when pressed with the tip of a knife. Mold is more likely to sit on softened or damp tissue and may have fine filaments. Do not use this check on dates that already smell bad or are visibly fuzzy; those have already failed the practical freshness test.
Crystallization can also become more visible as dates lose moisture, so an older but sound date may look paler and feel firmer without being moldy.
Sources
- UC Davis Postharvest Research and Extension Center — Date — Sugar spotting, fermentation, browning and storage disorders in dates.
- USDA FSIS — How should you handle food with mold on it? — Consumer guidance on visibly moldy foods and avoiding close sniffing.