Is tofu ultra-processed?

Plain tofu is group 3, and the reason is a useful one: it is made almost exactly the way cheese is. Soya beans are soaked and pressed into a milk, a coagulant such as calcium sulphate or nigari is added, and the curds are pressed. Milk, rennet, curds, pressing.

That places it beside cheese rather than beside the meat substitutes it sits next to on the shelf, which is a good illustration of the classification cutting across how a supermarket is arranged.

What is different

• Plain, firm, silken or smoked with actual smoke: group 3.
• Marinated or flavoured blocks: usually group 4, from the flavourings.
• Meat-substitute products made from soya or pea protein isolate, methylcellulose and flavourings: group 4, and not really the same category.
• Tempeh is fermented whole soya beans and is group 3.

The distinction worth holding is between a soya product made by curdling a milk, and one built from protein extracted from soya. The first is tofu, the second is a formulation, and protein isolates are what separates them.

Working this out from a receipt is harder than from a packet, because a till prints about twenty characters of product name and no ingredients list. That is the problem Bagged exists to solve, and how a receipt is structured explains why it is the hard part.