Summer Coolers, Hidden Dangers: When Freezing isn’t Enough!
Summer heat sends us running to freezers and ice chests. Whether it’s ice cubes in lemonade, frozen berries for smoothies, or ice cream at a cookout, cold foods feel like the safest bet when the temperature soars. After all, freezing is supposed to preserve food and keep it fresh.
But here’s the surprising truth: freezing doesn’t kill all pathogens. Many bacteria and viruses can survive frozen storage, ready to cause illness once the food is thawed or consumed. Outbreaks tied to frozen products — from berries to ice cream — remind us that “cold” does not always mean “safe.”
Why Freezing Doesn’t Guarantee Safety
Freezing slows bacterial growth but doesn’t destroy every pathogen. Some microbes can persist for months in cold environments. Once food thaws, they spring back to life.
- Bacteria like Salmonella can survive frozen storage and multiply after thawing.
- Viruses like Hepatitis A remain infectious in frozen fruits.
- Listeria monocytogenes is even more dangerous because it can grow slowly in refrigerated or frozen conditions.
This means frozen berries, ice cream, and even bagged ice can be vehicles for foodborne illness if contamination occurs at any point in the supply chain.
Case Study 1: 2015 Listeria Outbreak Linked to Blue Bell Ice Cream
In 2015, a beloved American brand became the center of a deadly outbreak.
- Impact: The CDC confirmed 10 illnesses across 4 states, with 3 deaths.
- Cause: Listeria monocytogenes was found in Blue Bell Creameries’ ice cream products. Investigators traced contamination back to unsanitary conditions in production facilities.
- Why it mattered: Ice cream is eaten frozen, without any kill step. Consumers had no way to protect themselves once contaminated products reached stores. The outbreak led to massive recalls and the temporary shutdown of Blue Bell’s plants.
Case Study 2: 2019 Hepatitis A Outbreak Linked to Frozen Blackberries
Frozen fruit may seem safe, but viruses can survive freezing — as the 2019 outbreak showed.
- Impact: The CDC reported a multistate outbreak of Hepatitis A linked to frozen blackberries sold under multiple brands. At least 11 illnesses and several hospitalizations were confirmed across states.
- Cause: Imported frozen blackberries carried Hepatitis A. Contamination likely occurred during harvesting or processing before freezing.
- Why it mattered: Consumers often ate the berries directly from the freezer in smoothies or desserts. Because freezing doesn’t kill viruses, every berry carried potential risk.
The Common Thread
Both outbreaks show how easily pathogens can infiltrate frozen foods:
- Once contaminated, freezing locks in the pathogen.
- Consumers rarely cook frozen foods like ice cream or berries, removing the chance for heat to kill germs.
- Recalls often come too late — by the time products are identified, they’ve been eaten.
What Consumers Can Do
While you can’t control processing plants, you can take steps to reduce risk:
- Check for recalls: Sign up for alerts from the CDC, FDA, or FoodSafety.gov.
- Wash before use: Rinse frozen fruits under running water if eating thawed.
- Heat when possible: If serving frozen berries in sauces or baked goods, cook them to 165°F.
- Clean ice makers: Mold and bacteria can build up in home or commercial ice machines.
- Practice “first in, first out”: Use older frozen foods before newer ones to avoid long storage times.
The Industry’s Responsibility
Producers and distributors of frozen foods must:
- Enforce strict sanitation protocols.
- Regularly test products for contamination.
- Train workers on safe harvesting and processing practices.
- Maintain transparent supply chains so recalls can be swift and effective.
Final Thoughts
Freezers give us peace of mind, but they’re not a silver bullet for food safety. The Blue Bell ice cream and frozen blackberry outbreaks remind us that pathogens can survive the cold.
The next time you grab ice cream at a cookout or toss frozen fruit into a blender, remember: freezing may pause bacteria, but it doesn’t erase them. Staying informed, handling food carefully, and supporting accountability in the industry are the real tools that keep summer treats safe.
