Freezing your shoes does not reliably kill the bacteria responsible for shoe odor. Standard home freezers operate around -18°C (0°F), and most bacteria survive these temperatures by entering a dormant state rather than dying. Once the shoes warm back up, surviving bacteria resume multiplying, and the smell often returns within days.
Why Freezing Doesn’t Kill Most Bacteria
Freezing is bacteriostatic, not bactericidal. That means cold temperatures stop bacteria from growing and reproducing, but they don’t destroy the cells outright. When researchers freeze bacteria even at temperatures far colder than your home freezer (down to -80°C and even in liquid nitrogen), survival rates typically range from 70% to 90%. A home freezer at -18°C is comparatively mild.
The bacteria most associated with foot odor belong to genera like Brevibacterium and Staphylococcus. Both are remarkably cold-hardy. Staphylococci show “good resistance to freezing” at both -20°C and -80°C in laboratory studies. Brevibacterium species have demonstrated survival rates of 80% to 100% after freezing and even freeze-drying, which is a far harsher process than anything your freezer can do. These are the exact organisms making your shoes smell, and they handle the cold just fine.
Freezing Won’t Help With Athlete’s Foot Either
If your concern goes beyond odor to fungal infections like athlete’s foot, freezing is equally ineffective. A 2022 study in the Journal of Fungi tested whether household freezing could kill the fungi responsible for skin infections. Freezing at -20°C for 24 hours, 48 hours, or even a full week failed to kill the fungal spores. Neither did direct heat exposure at 60°C for up to 90 minutes. These organisms are built to survive environmental extremes, and a trip through your freezer won’t eliminate them from contaminated shoes.
Why Freezing Seems to Work Temporarily
People who freeze their shoes often report that the smell disappears, at least initially. This isn’t because the bacteria are dead. Cold dramatically slows the chemical reactions that produce odor. The volatile compounds bacteria release (the ones your nose detects) are less likely to become airborne at low temperatures. So when you pull the shoes out, they smell fresh for a while. But as the shoes warm up and moisture returns from your feet during the next wear, the dormant bacteria wake up and get back to work. Most people find the odor returns within a few days of regular use.
What Actually Reduces Shoe Bacteria
Since freezing only pauses the problem, other approaches are more effective at genuinely reducing bacterial populations in shoes.
- Thorough drying: Bacteria and fungi thrive in moisture. Removing the insoles after each wear and letting shoes air dry completely between uses deprives them of their preferred environment. Rotating between two pairs of shoes gives each pair a full day to dry out.
- UV light: Ultraviolet shoe sanitizers are designed to kill bacteria and fungi inside shoes. These devices sit inside the shoe for several hours and expose the interior to UV-C light, which damages microbial DNA.
- Baking soda or antimicrobial sprays: Baking soda absorbs moisture and shifts the pH inside the shoe, making it less hospitable to odor-causing bacteria. Antimicrobial sprays containing alcohol or other disinfectants can reduce bacterial counts on contact.
- Washing: For shoes that can handle it (canvas sneakers, certain athletic shoes), a run through the washing machine with detergent is one of the most effective options. The combination of surfactants, agitation, and warm water physically removes bacteria rather than just inhibiting them.
If You Still Want to Freeze Your Shoes
Freezing won’t sterilize your shoes, but if you want to use it as a short-term deodorizing trick, there are a few practical considerations. Place the shoes in a sealed plastic bag before putting them in the freezer. This prevents any transfer of odor or bacteria to your food, and it keeps freezer moisture from soaking into the shoe material. Leave them in for at least 24 hours.
For leather shoes, repeated freeze-thaw cycles can draw oils out of the material, leaving it stiffer and more prone to cracking over time. The effect is gradual, but if you’re freezing expensive leather dress shoes regularly, you may notice changes in how the leather feels and ages. Canvas and synthetic shoes handle freezing with minimal concern.
The real limitation isn’t damage to your shoes. It’s that freezing addresses the symptom (the smell) without solving the underlying cause (a thriving bacterial colony in a warm, moist environment). Combining freezing with better moisture management and occasional disinfection will produce noticeably longer-lasting results than freezing alone.