The Vegan Society's official definition: veganism is 'a way of living which seeks to exclude, as far as is possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose.' For food, this means no animal-derived ingredients at all [1].
The obvious ones: no meat, fish, eggs, or dairy. But several less obvious ingredients also disqualify a product:
• Honey — produced by bees; not vegan in the strict definition [1] • Gelatin — made from boiled animal bones and skin; common in gummies, marshmallows, and some yogurts • Carmine / cochineal extract / Natural Red 4 — a red dye made from crushed cochineal insects, FDA-listed as a color additive [2]; used in red candies, yogurts, and beverages • Shellac (E904) — secreted by lac bugs, used as a glossy coating on candy and fruit • Lard, tallow, suet — animal fats, occasionally in baked goods and crackers • Rennet — enzyme from calf stomach, used to make most traditional cheeses (microbial and vegetable rennet alternatives exist) • Whey, casein, lactose, sodium caseinate — all dairy-derived, hide in unexpected places like protein bars, salad dressings, and 'non-dairy' creamers
Note that 'plant-based' on a label is NOT regulated to mean vegan. Many products marketed as 'plant-based' contain dairy or honey. The Academy of Nutrition and Dietetics confirms that a well-planned vegan diet is nutritionally adequate for all life stages but emphasizes that intentional planning matters — particularly for B12, iron, calcium, omega-3s, and vitamin D [3].
Rootd's vegan filter uses Open Food Facts's analysis tag plus an ingredient parser to catch these hidden non-vegan ingredients.