Which foods should a baby never have?

Short list, with the reason each one is on it.

Honey - not before 12 months. Risk of infant botulism from C. botulinum spores. This one is absolute, and it includes honey cooked into things.

Added salt - not at all in this window. Family food shared with a baby after 12 months should be prepared without added salt in the first place.

Added sugar and sweetened drinks - not at all. Juices are minimised. Water is the drink.

Whole nuts, seeds, hard or gummy sweets, popcorn, chewing gum, crisp fried snacks - avoid entirely until 4 to 5 years. This is a choking rule, not an allergy rule. Nuts are not off the menu: they belong in as smooth butter, paste or fine flour. Never whole, never in halves.

Raw or undercooked egg - cooked only. Egg should be in from early on, but heated. Raw pasteurised egg caused severe reactions in already-sensitised infants in trials.

The large predatory fish - avoid. Shark, swordfish, blue shark, pike, smooth-hound and large tuna carry the highest mercury. Fish itself is encouraged; it is these species and species monotony that are the problem.

Rice drinks - never. Inorganic arsenic. Ordinary rice is fine, and infant-grade rice is held to a stricter limit than standard rice.

Fennel tea - not under 4 years. Estragole. This surprises people, because it is sold as the gentle option.

Fresh and semi-fresh raw-milk cheese - not under 5 years. Well-aged raw-milk cheeses, Parmigiano Reggiano among them, are a different case and are fine.

Cured meats and salumi - not in the first year, and sparingly at most after.

What is not on this list

Nothing here says to delay an allergen to be safe. That is a separate question and the answer runs the other way.