What 'best by' really means

A long read

Before we start

This module is about United States date labels. There, almost no food has to carry a date at all, and the wording is left to the maker — which is a large part of why the dates mean so little. Canada does require a "best before" date on many packaged foods. The date is regulated there; what it tells you about quality and safety is still what this module explains.

Sources

USDA Food Safety and Inspection Service, "Food Product Dating" — Sell-By, Best if Used By and Use-By meanings; "except for infant formula, dates are not an indicator of the product's safety"
USDA FSIS, "Freezing and Food Safety" — 0°F inactivates microbes rather than killing them; frozen food stays safe indefinitely
USDA FSIS — canned shelf life (high-acid 12–18 months, low-acid 2–5 years); eggs 3–5 weeks refrigerated; the float test shows age, not safety
NRDC & Harvard Food Law and Policy Clinic, "The Dating Game" (2013) — >90% discarding food prematurely; infant formula as the only federally dated food
ReFED, 2024 U.S. Food Waste Report — household cost, national tonnage and value
U.S. EPA — food is the largest single material landfilled
FDA — foods at higher risk for Listeria: deli meats, hot dogs, soft cheeses, raw or smoked seafood, prepared deli salads, unpasteurised dairy

California AB 660 (Irwin), in force 1 July 2026 — two permitted phrases, consumer "Sell By" banned, applies to food manufactured on or after that date; eggs and infant formula exempt

FDA and USDA joint Request for Information on date labeling, opened late 2024

Canadian Food Inspection Agency — "best before" dating is required on many packaged foods in Canada, unlike the US

Read end to end and corrected: August 9, 2026. Numbers checked: August 9, 2026.