Cheddar

Cheddar is at the top of this axis for one reason: it is aged, and histamine climbs with ageing about as reliably in cheddar as in any cheese - mild at three months, extra-mature past two years, and the wrapper tells you which. There is no cheddar-wide figure worth quoting; there is a figure for the block in front of you, and its age is the best guide to it. Melting it changes nothing: histamine survives every temperature a kitchen reaches. Across a shelf of retail cheeses the spread is enormous and the variety is a weak predictor. Pasteurisation, starter culture, salt and ripening time are the real variables.

Cheddar is the cheese the 'cheese effect' was named after - the first MAOI hypertensive reactions in the 1960s were traced to it. Bacteria break the milk protein down over months and decarboxylate its tyrosine. The measured spread is enormous and that is the practical point: mild and processed cheddar average under 150 mg/kg, extra-sharp around 270, and the highest single sample on record reached 700 - you cannot tell which piece you have. For someone on a non-selective MAOI the dose commonly cited as dangerous is about 6 mg, which an extra-sharp cheddar delivers in roughly 25 g.

Mature cheddar is measured with no detectable lactose or galactose - but the word 'mature' is doing work in that sentence: the samples analysed were farmhouse cheddar, and a mild supermarket cheddar of a few weeks has not had the same time. The age on the packet is the number that matters, here as on the tyramine axis.