How to read a food label like a scientist

/ Food safety

Food safety

A food label is two things at once: real information and marketing. The skill is telling them apart. Once you know where the facts are and where the persuasion is, you read a label in seconds — and you make better products, because you know what your own label is really saying.

1. The ingredients list is ranked by weight

Ingredients are listed from most to least. Whatever is first makes up the largest share. This one rule tells you a lot — if sugar or oil sits near the top, that is what you are mostly buying.

Watch for split sugars. Sugar can appear under many names — cane sugar, glucose syrup, dextrose, fruit juice concentrate. Split across several names, each sits lower in the list, even when sugar is really the main ingredient.

2. Nutrition numbers: check “per 100 g” vs “per serving”

Nutrition information may be given per 100 g or per serving. A “serving” can be made small to make the numbers look better. To compare two products fairly, always compare the per 100 g column — it is the honest, like-for-like measure.

3. Some claims are regulated; many are just words

Specific, measurable claims usually have rules behind them. Vague, feel-good words often mean nothing:

  • Usually meaningful — “no added sugar”, “source of fibre”, a specific weight or percentage.
  • Often just marketing — “natural”, “premium”, “traditional”, “fresh”. These may sound reassuring but rarely guarantee anything specific.

4. Dates: quality versus safety

There are two kinds of date, and they mean different things:

  • “Best before” — a quality date. After it, the food may lose flavour or texture but is usually still safe.
  • “Use by” — a safety date, used on perishable foods. Do not eat these after the date.

5. Allergens should be clear

This is the line that protects people. Common allergens — peanuts, tree nuts, shellfish, fish, egg, milk, soy, wheat/gluten — must be easy to find. If you cannot quickly tell whether a product contains an allergen, that is a poorly made label, and on your own products it is a serious risk to fix.

6. Net weight, producer, and additives

Three quieter but important items:

  • Net weight or volume — how much you actually get, and the honest basis for comparing price.
  • Producer name and contact — a real, contactable maker is a sign of a trustworthy product.
  • Additives — preservatives, colours, and stabilisers are listed too. Not all are bad; many make food safer or last longer. The point is that they are declared, not hidden.

7. Storage instructions are part of the date

A date on its own is an incomplete statement. “Best before March” means best before March if the product is stored the way the producer assumed, and that assumption is printed alongside it: keep refrigerated, store in a cool dry place, consume within three days of opening. Read the two together, because the date stops being reliable the moment the storage condition is broken.

The after-opening instruction is the one shoppers most often miss. A sealed jar may keep for a year and only five days once opened, because opening it introduces air and microbes that the original process removed. That short second life is a genuine safety instruction, not a manufacturer being cautious.

Rule of thumb: if a product says “keep refrigerated” but you found it on an unrefrigerated shelf, the date on the pack no longer means what it says. Buy it somewhere that stores it properly.

8. Origin, importer and the language on the pack

An imported product should tell you where it came from and who brought it in. That importer or distributor detail matters more than it looks: it is the traceable party in your own country, the one who can be contacted if something is wrong with a batch. A pack with no local contact information at all is a pack nobody is accountable for.

  • A sticker over the original label is normal practice for imports, but check that it has not been placed over the date or the ingredients list.
  • Compare the sticker with what is underneath where you can see both. They should agree, particularly on the date and the allergen information.
  • Be cautious with a pack you cannot read at all. If nothing is in a language you understand, you cannot check allergens — and that is the one piece of information where guessing is genuinely dangerous.
  • Country of origin is about the food, not the company. A well-known brand name tells you who sells it, not where it was made.

9. A two-minute routine for any pack

You do not need to study every label in detail. A short, consistent routine catches nearly everything that matters.

  • Turn the pack over first. The front is designed to persuade; the back is where the regulated information lives. Start where the facts are.
  • Read the first three ingredients. They are most of the product. If sugar, oil or salt appears among them in something marketed as healthy, you have learned something the front of the pack did not tell you.
  • Check the allergen information, every time, if you or anyone you cook for is affected. Recipes change without announcement.
  • Look at the date and the storage line together.
  • Compare per 100 g, not per serving, if you are comparing two products.
  • Check the net weight against the price before deciding which pack is better value. A larger box is not always more product.
  • Inspect the pack itself — a swollen pouch, a lid that has lost its vacuum, a leaking seam or a dented can seam is a reason to leave it on the shelf whatever the date says.
Watch out: a label describes what should be in the pack, not what condition it is in now. Damaged packaging, a broken seal or a product that has clearly been stored badly overrides any printed date.

If you make food rather than only buy it, the same habits work in reverse. Everything above is what an informed customer, a retail buyer or an inspector will look for on your pack — so the fastest way to write a good label is to read a few dozen other people’s labels critically first.

The short version

  • Ingredients are ranked by weight — the first one dominates.
  • Compare nutrition per 100 g, not per serving.
  • Specific claims mean something; “natural” and “fresh” usually don’t.
  • “Best before” = quality; “use by” = safety.
  • Allergens must be clear; net weight and producer should be too.
A note on this article. This is general educational information. Labelling rules differ by country and product — if you are making a label to sell in Cambodia, follow the current national requirements (for example, the Cambodia Standard for food labelling) and confirm the details with the relevant authorities.

References & further reading

This article is general educational information, not a regulatory ruling. Verify the current labelling rules that apply in Cambodia or in your export market before relying on them.
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