Once opened, Juice, boxes keep about 8–12 days in the fridge. Unopened, they keep about Until the package use-by date.
8–12 days
That's the longest window published for Juice, boxes — opened in the fridge is its best case.
Source: USDA FoodKeeper v128 · Spoilage signs: U.S. Food and Drug Administration, Bacteriological Analytical Manual Ch. 22C · Category: Beverages
How long Juice, boxes keep
Situation
Keeps for
Unopened · pantry
Until the package use-by date
Opened · fridge
8–12 days
Only situations with a published figure are listed. A blank isn't “forever” — it means no reliable number is published for it.
Storage
Store at: Cool, dry pantry unopened; refrigerate at 40°F (4°C) or below after opening
Refrigerate after opening: Yes — refrigerate at 40°F (4°C) or below
Published storage guidance for Juice, boxes, from USDA Food Safety and Inspection Service:
Store cool and dry, under 85°F — heat shortens shelf life sharply“Store canned foods and other shelf stable products in a cool, dry place. Never put them above or beside the stove, under the sink, in a damp garage or basement, or any place exposed to high or low temperature extremes. Temperatures below 85 degrees F are best.” — USDA Food Safety and Inspection Service
The foil layer is what keeps it shelf-stable without preservatives“Aluminum (6%) is the silver material on the inside of the aseptic package. This ultra-thin layer of foil forms a barrier against light and oxygen, eliminating the need for refrigeration and preventing spoilage without using preservatives.” — USDA Food Safety and Inspection Service
How to tell if Juice, boxes has gone bad
Specific to Juice, boxes, published by U.S. Food and Drug Administration, Bacteriological Analytical Manual Ch. 22C:
Fizzing in a still drink, or a swollen carton or can
A bitter or 'off' first sip
The first list is quoted from U.S. Food and Drug Administration, Bacteriological Analytical Manual Ch. 22C, with the page each line came from linked beside it; the rest are the general signs for beverages. Never taste something to test it — when in doubt, throw it out.
Air and warmth are what shorten an opened item's life — the right container buys back the days the packaging gives up once the seal's broken.
About 8–12 days refrigerated at 40°F (4°C) or below, according to USDA FoodKeeper v128. Refrigerate it once it's open.
Do Juice, boxes need to be refrigerated after opening?
Yes — keep Juice, boxes at 40°F (4°C) or below once it's open. Cool, dry pantry unopened; refrigerate at 40°F (4°C) or below after opening.
How can you tell if Juice, boxes are bad?
A swollen or bulging carton — do not drink it; A rotten or putrid smell on opening; Leaks or a damaged seam — the sterile seal has failed. That guidance is published for Juice, boxes by U.S. Food and Drug Administration, Bacteriological Analytical Manual Ch. 22C. Beyond that, the general signs for beverages are: Sour or off smell; Cloudiness, sediment, or curdling; Fizzing in a still drink, or a swollen carton or can; A bitter or 'off' first sip. Never taste something to test it — when in doubt, throw it out.