What Makes a Freezer Bag Different From a Storage Bag

What freezer burn is, in FDA’s words

FDA’s consumer page Are You Storing Food Safely? has a short section it calls “Freezer Facts,” and three of its sentences do most of the work here.

The first is about safety. “Food that is properly handled and stored in the freezer at 0° F (-18° C) will remain safe. While freezing does not kill most bacteria, it does stop bacteria from growing.” FDA adds that food “will be safe indefinitely at 0° F,” while “quality will decrease the longer the food is in the freezer. Tenderness, flavor, aroma, juiciness, and color can all be affected.”

The second is the definition. “Freezer burn does not mean food is unsafe. Freezer burn is a food-quality issue, not a food safety issue. It appears as grayish-brown leathery spots on frozen food.”

The third is the cause, and it is the sentence a bag is sold against. Freezer burn “can occur when food is not securely wrapped in air-tight packaging, and causes dry spots in foods.” Elsewhere on the same page FDA says leftovers “should be stored in tight containers.” Air reaching the food is the mechanism, in the agency’s own description, and keeping air out is the job.

What a freezer bag claims that a storage bag doesn’t

Glad sells both kinds under the same zipper-lock name, and its two pages divide the claims between them. Runlow’s records hold one of each in the gallon size.

The freezer bag’s page leads with the claim: “Prevent freezer burn thanks to an airtight zip-lock seal and extra-thick durable plastic.” The brand’s own comparison grid, which appears on both pages, lists the freezer bag’s benefit as “prevents freezer burn” and its use as “freezing & marinating.”

The storage bag’s page describes the bags as “resealable, tight-closing,” and the same grid gives this bag a different benefit, “locks in freshness,” and a different use, “marinating & travel.” The “prevents freezer burn” line is not on its side of the grid.

Two things neither page states, and the records say so. Neither names the plastic the bag is made of, and neither states a thickness. “Extra-thick” is a comparison the brand draws against its own storage bag, and a reader has no number from the brand to put beside it. Neither page states a pack count either, so each record carries the bag’s capacity as its unit.

What FDA says about storing food, bag or not

The same FDA page carries the rules that apply before any bag enters it. Refrigerated foods should be stored “in covered containers or sealed storage bags,” and leftovers checked daily for spoilage. Perishables go into the refrigerator or freezer “as soon as you get them home,” under the “two-hour rule”: nothing that needs refrigeration sits out “for more than two hours—one hour if the air temperature is above 90° F,” and that includes leftovers and take-out.

On temperature, “the refrigerator temperature should be at or below 40° F (4° C). The freezer temperature should be 0° F (-18° C).” FDA recommends an appliance thermometer in each, “in the front in an easy-to-read location,” checked at least once a week. And if the power goes out, “a full freezer will keep an adequate temperature for about 48 hours if the door remains closed,” while a refrigerator “will keep food cold for about four hours if it’s unopened.” Food that “still contains ice crystals or is 40 °F or below” when power returns “is safe to refreeze or cook,” in FDA’s words.

Runlow carries records for two Glad bags in this category and none from any other brand, so this post names no other product. When more exist, the freezer statement, the closure and the material will render from each record, the way every product fact on this site does.

Where this comes from

Every regulatory statement above is quoted from FDA’s consumer update on storing food safely, linked in the text. Every product statement is quoted from Glad’s own two product pages, read on October 6, 2026 and sourced on each record. Runlow has not tested either bag, and nothing here is food safety advice beyond what FDA’s page itself says.