IN MY more squeamish, younger days, when reading Russian literature, I would perforce stop, faintly nauseated, at passages where characters helped themselves to a cup of warm fermented mare's milk. That, like the skin that would form on a French cafe au lait if not served piping hot, seemed to me beyond the bounds of decency. Indeed, I have eschewed milk nearly all my life - the one exception being a not very prolonged fling, in adolescence, with milk drunk as an accompaniment to asparagus.

There are no doubt psychological explanations for this, and I recall with shame that when in childhood I wished to hurt my mother - a woman of great gullibility and an absolute Italianate belief in the perfection of her children - I would say that most of my maladies were a result of breast-feeding, going so far on several occasions as to tell her that I could well recall from those far-off days that her milk was sour. Make of that what you will, but no one can convince me that milk is not dodgy stuff.

That is why I am puzzled at the spread in our own culture of the very thing that makes milk unacceptable to me: its tendency to go off. People who put sour cream on their baked potatoes strike me as daft; so are all eaters of yoghurts, drinkers of buttermilk and so on. I can see the use (occasionally and in small quantities) for these products in otherwise overpowering dishes such as a borsch, but otherwise who likes things that are definitely 'off'?

My feeling about fermented mare's milk and other terrible concoctions of the Mongols and Tartars is, I think, historical. In two ways. First, in my formative years a string of tutors found it necessary to point out that with the invasion of the golden hordes, all civilisation came to an end. That to me meant that good cooking went, to be replaced by barbaric customs such as drinking sour milk.

Second was the fact that quite clearly as one grew up one should set aside childish things such as milk. 'Drink up your milk' seemed to me a command to remain infantile, and I rebelled.

Then, when evacuated to the United States, I found myself surrounded by a people who seemed to live on the stuff. Good grief] Grown men drank it with their lunches. The American fridge, that unheard-of marvel, would open up to reveal quarts and gallons of it. It was not until much later that I realised what a con the whole milk thing was. The US had been persuaded that milk was healthy, nay vital; being a natural product passed on to us directly from nursing cows (not sheep, goats or mares in the US), it was the source of the great American wholeness, of its good nature, its heartiness.

Well, I was against that, too, and I blamed milk for many of the equivalent defects of the American character: a tendency to blandness and to fat, an aversion to growing up entirely, a streak of gentle complacency. So when, decades later, milk took a few knocks (it was not all that good or nutritious, it was not strictly necessary even for young children), I celebrated.

Then the other day I was asked why certain cultures took to milk in a big way and others did not. Thinking about the matter, I came up with a first facile theory: that obviously one used the products to hand. For instance, milk is something of a rarity in Italy and not much favoured in France. Was this because Italians bred cattle for meat rather than milk? And then really only in the north? Mediterranean culture as a whole is not strongly pro-milk; northern cultures tend to be.

The availability theory did not entirely fit, for countries that did not much fancy milk did fancy cheese and consumed it in vast quantities and many varieties - while the US, where milk is idolised, has no cheese worth eating.

The obvious non-milk cuisines are Chinese and Japanese. Edward H Schafer points out, in his essay on T'ang food, that: 'We are accustomed to the idea that there is a line which divides eastern Asia into two cultural groups - one of which depends on milk and milk products (Indians, Tibetans and many Central Asian nomads), and one which rejects them with loathing. In the latter group we place the Chinese.'

Nicely put. Succinctly put. But even the Chinese adapted: primarily for religious reasons, the various stages of the decomposition of milk are regarded as analogous to the soul's progress towards perfection.

My spirit tells me that it would be ancient civilisations that gave up on milk in their childhood, but this is evidently not true. Anyone who has seen Indian street vendors frothing up their milk by tossing it in great arcs between two goblets knows that Indians are so dotty about the stuff that they even corrupt their tea with it.

Does the distinction lie between hot countries and cool? No, because both North Africa and the Middle East have strong milk traditions, while the sensible Eskimos have none. At this point I know you are expecting me to come up with an answer. I have none. I suspect the answer may be philosophical and draw on some line between what is purely natural, a base ingredient, and what is created, with art, an ingredient transformed. While I am in China, I hope to receive a nutritious correspondence on this score.