Difference Between Use-by Date and Best-before Date

FOOD SAFETY AND QUALITY ASSURANCE: DATE MARKS

Diagram

Figure 1: A use-by date is about safety and a best-before date is about quality. Drawn in our own style from the FTN Food Safety and Security notes, Unit 5, and from Emerson, Read the Label!.

Introduction

A use-by date and a best-before date are the two date marks printed on food packs, and both tell the eater something about time, but they answer different questions. A use-by date is about safety: food past its use-by date may be unsafe even if it looks fine, and it should not be eaten. A best-before date is about quality: food past its best-before date may lose taste or texture, but it may still be safe if it was stored correctly. Emerson, Read the Label!, opens with the same question: do you know the difference between use by and best before?

The FTN Food Safety and Security notes, Unit 5, call the label a safety document and warn that confusing the two date marks causes harm in both directions. This article follows that unit, with Emerson.

Quick comparison

Table 1: Use-by date compared with best-before date

Scientific explanation

Definition

A use-by date is a date mark about safety: food past its use-by date may be unsafe and should not be eaten. A best-before date is a date mark about quality: food past its best-before date may lose taste or texture but may still be safe. The two marks sit on the same label, but they are set for different reasons and read in different ways.

Working principle

A food label is not only marketing: it is a safety document that tells the eater what is inside, how to keep it, how to use it, and who made it. The core items on a label are the name of the food, the list of ingredients in order of amount, the allergens named clearly, the net quantity, the date mark, the storage instructions, the instructions for use, and the name and address of the business. Date marks need care. A use-by date is about safety: food past its use-by date may be unsafe even if it looks fine, and it should not be eaten, because pathogens can grow to a harmful level without changing the look, smell or taste of the food, so the senses cannot judge whether it is safe. A best-before date is about quality: food past its best-before date may lose taste or texture, but it may still be safe if it was stored correctly. Confusing the two causes harm in both directions: people eat unsafe food, or they throw away safe food.

Apparatus

The books used here name no laboratory apparatus for telling the two apart, so no apparatus list is given.

Measurement procedure

The books used here name no single standard laboratory procedure for telling the two apart. The distinction is made from the definitions and properties given above, not from one test.

Factors affecting readings

Storage decides whether either date holds: both dates assume the food was stored as the label says, so a chilled food left warm loses its safety margin, and a dry food kept damp loses its quality early. The food itself decides which mark it carries: perishable foods that grow pathogens carry a use-by date, while long-life foods that only lose quality carry a best-before date. Time matters in both directions: eating past a use-by date risks illness, and throwing away food past a best-before date wastes food that may still be safe.

Formulas and calculations

The books used here give no formula for this comparison, so no formula or worked calculation is given.

Industrial applications

• Use-by date: fresh milk, which carries a use-by date because it can grow pathogens.
• Use-by date: fresh meat and ready meals, which must not be eaten past the date even when they look fine.
• Use-by date: the mark a shop checks when it clears chilled shelves.
• Best-before date: dry biscuits, which carry a best-before date because they lose texture, not safety.
• Best-before date: cereals and canned foods, which keep their safety long after their quality fades.
• Best-before date: the mark a cook reads to judge taste and texture, not safety.

Advantages and limitations

• Use-by date, advantage: it protects the eater from pathogens that cannot be seen, smelled or tasted.
• Use-by date, limitation: it is strict, so food past the date must be thrown away even when it looks fine.
• Best-before date, advantage: it tells the eater about quality without forcing safe food to be thrown away.
• Best-before date, limitation: it is only about quality, so it gives no warning when a food becomes unsafe for another reason.

FAQ

What is the main difference between a use-by date and a best-before date?

A use-by date is about safety: food past it may be unsafe and should not be eaten. A best-before date is about quality: food past it may lose taste or texture but may still be safe.

Can I eat food past its best-before date?

It may still be safe if it was stored correctly, but it may have lost taste or texture, so judge it by eating quality, not by safety alone.

Why should food past its use-by date not be eaten even when it looks and smells fine?

Because pathogens can grow to a harmful level without changing the look, smell or taste of the food, so the senses cannot judge whether it is safe.

Which foods carry a use-by date?

Perishable foods such as fresh milk, fresh meat and ready meals, which can grow pathogens.

Which foods carry a best-before date?

Long-life foods such as dry biscuits, cereals and canned foods, which lose quality rather than safety.

References and further reading

• FTN subject: Food Safety and Security, Unit 5: Food Safety Management Systems and Food Law.
• Richard Emerson, Read the Label!: Discover What Is Really in Your Food, Random House, 2012 (Google Books page read)