How Long Does Milk Last? A Complete Guide to Dairy Storage and Food Safety
The most common dairy food waste scenarios share a single cause: confusion between "best before" and "use by" dates, and uncertainty about what spoiled dairy actually looks like. In the UK, the Food Standards Agency distinguishes sharply between these two labels. "Use by" is a safety date: food should not be consumed after this date regardless of appearance or smell. "Best before" is a quality date: food remains safe but may have declined in quality. Most dairy products carry "use by" dates rather than "best before" dates, which means the date on the carton is not optional. However, the use by date is based on an unopened product stored at the correct refrigerator temperature; once opened, dairy products typically have shorter safe lives than the printed date.
Milk
Pasteurised Whole, Semi-Skimmed, and Skimmed Milk
Unopened and refrigerated at 1 to 4°C: safe until the printed use-by date (typically 10 to 21 days from pasteurisation date depending on retailer supply chain).
After opening: 7 to 10 days at correct refrigerator temperature. The act of opening exposes the milk to bacteria from the environment; each subsequent pour introduces additional bacteria if the carton lip is contaminated. Pouring milk into a glass rather than drinking directly from the carton significantly extends shelf life by reducing bacterial contamination of the bulk container.
Correct refrigerator storage temperature: 1 to 4°C. A DEFRA study found that 28% of UK domestic refrigerators operate at above 8°C, which reduces milk shelf life substantially. Store milk at the back of the refrigerator (coldest), not in the door (warmest).
UHT (Ultra-Heat Treated) / Long-Life Milk
Unopened at room temperature: 6 to 12 months (product dependent; date on carton). The high-temperature treatment (135°C for 2 to 4 seconds) eliminates virtually all bacteria and spores. UHT milk has a slightly cooked, caramelised flavour compared to fresh pasteurised milk due to Maillard reactions during high-heat processing.
After opening: treat as pasteurised milk; use within 7 to 10 days, refrigerate after opening.
Raw (Unpasteurised) Milk
Significantly shorter shelf life than pasteurised milk: 2 to 4 days refrigerated after purchase, as the naturally occurring bacteria populations continue to multiply without the inhibition that pasteurisation provides. Raw milk spoils differently from pasteurised milk: it sours rather than rotting (the bacterial conversion of lactose to lactic acid produces a tangy, yogurt-like product rather than the genuinely off-putting smell of spoiled pasteurised milk). Traditional cultures used this souring process deliberately to produce early forms of cultured dairy.
Can You Drink Milk After the Use-By Date?
Milk carries a "use by" date (not "best before"), which means the Food Standards Agency classifies it as a safety date. Unlike "best before" dates (which relate to quality), use-by dates should not be exceeded. However, unopened pasteurised milk kept consistently at 1 to 4°C will often remain organoleptically (smell, taste, appearance) acceptable for 1 to 3 days beyond the use-by date. The smell test is reasonably reliable for pasteurised milk: sour, unpleasant, or "off" smell indicates it has spoiled; clean, milky smell typically indicates it is still safe. The visual check for curdling or separation is also useful. That said, the use-by date represents the manufacturer's tested safety guarantee, and choosing to consume milk after that date is a personal risk decision.
Dairy Product Storage Guide
| Product | Unopened | After Opening | Freezer |
|---|---|---|---|
| Pasteurised milk | Until use-by date | 7 to 10 days | 3 months (texture changes) |
| UHT milk | 6 to 12 months (ambient) | 7 to 10 days (refrigerated) | Not recommended |
| Double/heavy cream | Until use-by date | 3 to 5 days | Not recommended (separates) |
| Sour cream / crème fraîche | Until use-by date | 7 to 14 days | Not recommended (texture changes) |
| Plain yogurt | Until use-by date | 5 to 7 days | 1 to 2 months (texture changes) |
| Butter (salted) | Until best-before date | 1 month refrigerated; 1 to 2 weeks at room temp | 6 to 12 months |
| Butter (unsalted) | Until best-before date | 2 to 3 weeks refrigerated | 6 to 9 months |
| Hard cheese (cheddar, parmesan) | Until best-before date | 3 to 4 weeks (wrapped) | 6 months (grated); 2 months (block, texture changes) |
| Soft cheese (brie, camembert) | Until use-by date | 3 to 5 days | Not recommended |
| Cottage cheese | Until use-by date | 5 to 7 days | Not recommended (watery texture) |
| Mozzarella (fresh, in liquid) | Until use-by date | 3 to 5 days in brine | Not recommended |
| Cream cheese | Until use-by date | 10 to 14 days | Not recommended (texture separates) |
How to Tell If Dairy Has Spoiled
- Milk: Sour smell (even mild); visible curdling or clumping when poured; yellowish colour (normal is bright white). Slight thickening without visible clumps may still be acceptable.
- Cream: Sour smell; lumpy or curdled texture; fails to emulsify when stirred. Slightly thickened cream may still be safe if smell is normal.
- Hard cheese: Surface mould on hard cheese can be cut off with a 2.5cm margin all around; the remainder is safe to eat (the mould cannot penetrate deeply into hard cheese). Do not use this approach with soft cheeses.
- Soft cheese and cream cheese: Any surface mould means discard the entire product; mould spreads through soft cheese easily.
- Butter: Rancid, soapy, or cheesy smell indicates the fat has oxidised. Surface yellowing is normal (oxidised outer layer); scraping the surface reveals fresh butter underneath in most cases.
- Yogurt: Pink, orange, or green mould growth visible; significantly more sour than normal; watery liquid (whey separation is normal and safe; watery with off smell is not).
Related: Types of Cheese: The Complete Guide | Heavy Cream vs Double Cream: Every Cream Type Explained