Every storage time on this site comes from one official source: the USDA Food Safety and Inspection Service FoodKeeper dataset. This page explains exactly what we do with that data — and, just as important, what we refuse to do.
Where the numbers come from
We download the English FoodKeeper JSON published through catalog.data.gov and pin it as a snapshot. The site you are reading runs entirely from that pinned copy — no live calls to USDA servers. The current snapshot is dataset version 128 (upstream modified 09-06-2018), retrieved 2026-07-24, verified by SHA-256 checksum. Full provenance is on the sources page.
How records become pages
The dataset contains 661 product records. Records that share a name — for example the many cuts of ham — are grouped onto one page as selectable varieties, so “How long does ham last?” has one canonical home. Each variety keeps its own official guidance; we never merge, average, or reconcile numbers across varieties, because a bone-in ham and a canned ham are genuinely different answers.
Each record can carry guidance for the pantry, the refrigerator, and the freezer, in up to four conditions taken directly from the source: general, from date of purchase, after opening, and after thawing. We preserve the USDA wording and units (days, weeks, months, years — and qualitative values such as “Not Recommended” or “Package use-by date”) exactly as published.
What we never do
- No invented numbers. If the source lists no duration for a combination, the site says “No official duration listed” and suggests a next step. It never estimates.
- No safety promises. A storage window is a guideline for quality and safe handling under the stated assumptions. It is not evidence that a specific item in your kitchen is safe — and neither smell, appearance, nor a calculated date can prove that.
- No spoilage diagnostics or medical advice. For guidance involving vulnerable people (pregnancy, young children, older adults, weakened immune systems), we link to FoodSafety.gov rather than writing our own rules.
Freezer times mean quality
Food kept constantly frozen at 0 °F (−18 °C) stays safe indefinitely. Freezer ranges in the dataset describe how long quality holds up, so we label them “best quality” wherever they appear. Refrigerator and pantry windows, by contrast, do bear on safety and assume proper temperatures — 40 °F (4 °C) or below in the refrigerator — and prompt storage.
Date calculations
The “stored on” calculator adds the official minimum and maximum duration to your date using calendar-aware arithmetic: months respect actual month lengths (January 31 + 1 month = February 28, or February 29 in a leap year), and leap years are handled correctly. The result is shown as a window, together with the guideline and its assumptions.
Validation
Every data refresh runs automated checks: malformed or negative durations, minimums greater than maximums, unsupported units, duplicate identifiers, empty names, and records pointing at unknown categories all fail the build. Oddities that are genuinely in the source (for example, prose inside a numeric field) are preserved verbatim and noted in the data-quality report we generate with every refresh (summarized on the sources page). The build refuses to ship with blocking errors.
Before a new source snapshot is published, editor Bineyam Tsegaye also checks a fixed sample of common and structurally difficult foods against the official FoodKeeper source. That sample covers multiple varieties, after-opening guidance, qualitative entries, freezer-quality wording, and source fields that contain prose instead of ordinary numbers.
Limitations
- The upstream dataset was last revised by USDA in 2018; it remains the current published version. We re-check for updates and re-ingest when USDA publishes changes.
- Guidance is generic per food type. Packaging, additives, and handling vary by product — the package label always wins when it is stricter.
- Times assume food was handled safely before storage (the “two-hour rule” and proper temperatures). They cannot rescue food that was mishandled.
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