Methodology · Food

How Luminelle scores food.

Scan a food barcode and Luminelle gives it a score from 0 to 100 with the reasons behind it. The score weighs three things - how the product fares nutritionally, what the additives in it are known to do, and how processed it is - and every additive level points to the regulator or study it comes from. It is not medical advice, and it never calls a legal product dangerous.

Cosmetics are scored differently. That method is on the cosmetic methodology page.

The short version

• Nutrition is worth 60 points, additives 30 and processing 10.
• A high-risk additive, processed meat or a Nutri-Score E caps the score at 49, the top of “Poor”, however good the rest looks.
• Each additive level is a rule applied to a regulator's finding, with the source one tap away.
• No ingredient list means no overall score. A missing list is never read as “no additives”.
• Personal notes - pregnancy guidance, and ingredients you've asked us to point out - are shown beside the score and never change it.

The formula

The three parts are added and rounded, then capped at 49 if any cap applies. Labels follow the score: 90 and above is Excellent, 70 Good, 50 Fair, and below 50 Poor.

Nutrition

Nutrition is the Nutri-Score under its 2023 algorithm, as computed by Open Food Facts from the product's nutrition table. It counts energy, sugars, saturated fat and salt against protein, fibre and fruit, vegetables and legumes, with separate tables for drinks, for fats, oils, nuts and seeds, for cheese and for red meat. Where a product has to be prepared, the prepared values are used. Open Food Facts tells drinks from foods by their categories. So when a product whose first ingredient is carbonated water has been graded on the food table, we grade it again as a drink from the same figures.

Each letter owns a band of the 60 points, and within the band fewer Nutri-Score points score higher. The letter decides the band, so a B can never score below a C.

When we call sugars, saturated fat or salt low, moderate or high, we use the UK front-of-pack traffic-light thresholds per 100 g, or per 100 ml for drinks. These words don't change the score; they describe the label. Nutri-Score's own points run on a stretched scale, so 33 g of sugar is only 9 of 15 points. DHSC/FSA guidance, November 2016.

Additives

The additive part starts at 30. Each additive is given the highest level whose rule it meets, and each level takes points once per risk group - three azo colours cost the same as one, because the finding is about the group. Anything not in the knowledge base is shown as not assessed and costs nothing.

These are the additives with a level above no concern, and the source each one rests on.

Regulatory status is shown as fact next to the level - “banned as a food additive in the EU since 2022”, “US FDA revoked” - and a product sold legally is described as legal. The words used are the regulators' own.

Processing

Processing is the NOVA group Open Food Facts assigns from the ingredient list: 1 unprocessed or minimally processed, 2 a processed culinary ingredient, 3 processed, 4 ultra-processed. The app shows what put a product in its group, such as a flavouring or an emulsifier. When the group can't be worked out, the part scores 5 of 10 and says so. Plain water with nothing added counts as unprocessed.

US products

About half of the US products in Open Food Facts are missing an ingredient list or a full nutrition table. When a product is missing, or can't be scored from Open Food Facts, Luminelle looks it up in USDA FoodData Central, the US Department of Agriculture's public database of manufacturers' labels. A USDA record is only used when it can be scored in full, and replaces the Open Food Facts one whole rather than being mixed with it.

USDA publishes no Nutri-Score, so Luminelle computes one from the label, to the same 2023 rules; our implementation matches Open Food Facts' grade and points on every product we test it against where Open Food Facts scored the label itself rather than estimated values. Three differences are marked as estimated in the app, and each can only lower a score:

• US labels don't state the share of fruit, vegetables and legumes, so it counts as zero - except for 100% juices.
• Where a label omits sugars or saturated fat but gives carbohydrates or total fat, the missing line is scored at its ceiling.
• Additives are found by name (“Red 40”, “mono- and diglycerides”), and processing is only ever read as ultra-processed or unknown - text alone can't prove a food is unprocessed.

Processed meat

IARC classifies processed meat - cured, smoked or salted, including “uncured” products preserved with celery powder - as carcinogenic to humans (Group 1), based on colorectal cancer. Any processed meat is capped at 49 whatever additives it lists, so a nitrite-free label can't outscore the product it replaces.

Your food preferences

In Settings you can ask Luminelle to point out seed oils, added sugar, flavourings, gums and thickeners, artificial sweeteners or palm oil. A product that contains one gets a note under “For you”. These are preferences, not findings: several are popular rules that the evidence doesn't support as health risks - the American Heart Association still recommends seed oils over saturated fat - so they never move the score.

Labels are checked the same way whatever language they're printed in. Open Food Facts reads each ingredient into a language-neutral entry - dextrose, zahăr and Zucker all become added sugar - and we check those entries, and the label text only for what it couldn't read. If too much of a list can't be read, the note says so rather than staying quiet. Pregnancy notes work the same way.

When there is no score

• Nutrition only. The ingredient list is missing, or too much of it couldn't be read (more than 30% unrecognised, though one unrecognised ingredient is fine on a list of three or more). The Nutri-Score part is shown; the total is not. Single-ingredient foods - water, oils, honey, eggs, plain nuts - are scored without a list.
• Not enough data. The nutrition table is missing or physically impossible, for example more calories in kcal than in kJ. It is also not scored when the kcal and kJ figures can't describe the same 100 g (more than 20% apart). That usually means some figures are per serving.
• Not rated. Nutri-Score doesn't rate alcohol, chewing gum, baby food, supplements, or plain tea, coffee, herbs and spices, so neither do we.

Sources and licences

Product data contains information from Open Food Facts, available under the Open Database Licence.

Changelog

Corrections

If you think an additive is at the wrong level, or a source is out of date, write to info@luminelle.ai with the citation.