The history of humanity's engagement with milk is as much one of fear and revulsion as it is of pleasure and nutrition. For the Greeks and Romans, milk was for infants or to be poured on altars as sacrifice (for the most part it was preserved as cheese): it was the barbarians who ate raw flesh and drank milk. Long before the late 19th-century discovery that its combination of sugars and proteins was the perfect breeding ground for bacteria, milk was viewed with suspicion. Quick to sour and spoil, difficult to transport any distance, it remained for a long time something less than civilised.
For all its bucolic associations, there is something oddly unnatural about milk. It is diverted for human consumption from the infant animals for whom it is intended, infants who are produced in order to secure the milk supply and who are often destined to die early (we find a recognition of the dubious morality of this act of theft and sacrifice in the ancient Hebraic injunction against seething the kid in the milk of its mother).
This is not an aspect of food politics that interests Deborah Valenze, but she is acute on another of the ways in which animal milk is unnatural for humans: the fact that a large proportion of the world's population is unable to digest it. Lactose intolerance is actually the "natural" human state, but some populations have evolved the ability to process this milk sugar, possibly because the calcium compensates for reduced absorption of vitamin D in regions further from the equator. In fact, as Valenze explains, "lactose tolerance" is a misnomer - what those of (mostly) northern descent actually possess is "lactase persistence": the enzyme lactase that enables the infant body to break down lactose unusually persisting beyond weaning.
Milk is an awkward reminder of our mammalian nature. Valenze discusses breast milk alongside that of other mammals throughout her narrative. Lactating medieval saints (both male and female) abut her narrative of the development of Italian cheese-making (taking in Boccaccio's famous mountain of parmesan) and she gives an interesting account of the use of breast milk as medicine in 16th-century Britain.
The attempts of milk reformers to clean up the contaminated and adulterated milk supply weave through the history of breastfeeding and its rises and falls in fashion from the 18th to the 20th centuries, demonstrating effectively her final contention that throughout its complex history milk has always been understood in terms of children and health.
Moving from the Hindu myth of the origin of stars, Moon and Sun as butter churned from an ocean of milk through the fermented mare's milk that chiefly sustained Genghis Khan and his men, to the milk bars of the 1960s (via the troubled state of Thomas Carlyle's stomach), Valenze's account of milk ranges far in both historical and disciplinary terms.
I would have welcomed something on the recent rise in the consumption of milk and its products in the previously dairy-free China and Japan, and an explanation of the curious ubiquity of tinned milk products in Latin American food culture, but for the most part the narrative sticks, reasonably enough, with the dairy-rich regions of Northern Europe and the US. It strays frequently into the realm of cheese-making (curiously, since cheese might be said to be conceptually the opposite of milk: aged, cultured, rotted and solid rather than young/raw, natural, uncivilised and liquid) and dwells briefly on milk chocolate, but is virtually silent on other milk products such as yoghurt and cream.
Valenze's book is an engagingly written and well-researched foray into a huge territory, pulling a mass of material into sharp focus and revealing milk as both strange and familiar.
Milk: A Local and Global History
By Deborah Valenze. Yale University Press, 352pp, £17.99. ISBN 9780300117240. Published 28 July 2011