A survey was undertaken to update and extend information on the water‐soluble vitamin content of milk and milk products on retail sale. The results are discussed in relation to previously published data. Apart from vitamin C the levels of vitamins in retail pasteurized cows' milk were very similar to those found in milk from the processing dairy. Levels of total vitamin C and folic acid in UHT full cream milk were negligible; vitamin B6 and vitamin B12 were respectively 73 and 56% of the levels in pasteurized milk. Except for nicotinic acid, pantothenic acid and biotin, the levels of vitamins in sterilized milk were lower than in pasteurized milk, particularly vitamin C, folic acid and vitamin B12. When compared on an equivalent dilution basis, vitamin B6, thiamine, folic acid and, especially, vitamin B12 in evaporated milk were lower than in pasteurized cows' milk. In comparison, in full cream condensed milk only vitamin B6 was particularly low; vitamin C was particularly well preserved. With the exception of vitamin B12, vitamin levels in reconstituted spray dried milk were similar to those in pasteurized cows ‘milk. Levels in filled’ spray dried milk were on average 70% of those in ordinary dried milks. Apart from vitamin B12 the levels of B vitamins in non health food yogurt were generally higher than in pasteurized milk, especially folic acid. The levels of vitamin B12 and folic acid in goats' milk were only 22 and 11 % respectively of those in cows' milk, but the nicotinic acid level was four times higher. The level of vitamin C in raw sheep's milk was about five times that in pasteurized cows' milk; other levels, apart from folic acid which was similar, were between 1.3 and 5.2 times those in cows' milk.

Although the composition of cow's milk has been studied by many workers, there is relatively little published information on ewe's milk and information on its content of amino acids and B vitamins is sparse and incomplete.In the present study, determinations have been made of the major constituents of ewe's milk, of its amino acid composition and its content of 8 vitamins of the B-complex. MATERIALS AND METHODSAnimals and their management. Six 2-year-old Suffolk x Clun Forest ewes were used in the experiments. They were maintained on a high plane of nutrition with a daily diet of hay and concentrates (hay 1-1 kg; barley 320 g; flaked maize 160 g; bran 80 g, linseed oil cake 40 g) with added minerals and vitamins as described by Braithwaite, Glascock & Riazuddin (1969). The ewes were machine-milked twice daily and samples of the bulked morning and evening milks were stored at -20 C C to await analysis. Individual samples were taken from 3 of the ewes on the ninth, fourteenth and nineteenth days of lactation for the vitamin analyses.For all other analyses samples of milk taken from all 6 ewes on the second, twentyfirst and forty-ninth days of lactation were used. A composite sample of cow's milk from a bulk tank from the Institute's herd of Friesian cows was included for comparative purposes.Methods of analysis. Samples were analysed for fat content by the Gerber method (British Standards Institution, 1969), for total solids by drying at 100 °C, for total N by the Kjeldahl technique, for lactose by the chloramine-T method (British Standards Institution, 1963) and for ash after heating at 500-550 °C (British Standards Institution, 1963). Solids-not-fat content was calculated by difference. Assays for riboflavin, thiamin, vitamin B 12 and folic acid were done as described by Ford et al. (1969) and those for nicotinic acid, biotin and pantothenic acid as described by Chapman et al. (1957). Vitamin B 6 was assayed as described by Gregory (1959). Most amino acids were determined, after hydrolysis by refmxing with 6 M-HC1 at 110 °C for 24 h, by the method of Spackman, Stein & Moore (1958) using a multichannel amino acid analyser (Evans Electroselenium Ltd, Halstead, Essex, England). Cystine and methionine were determined by the method of Moore (1963) using a JLC-5AH amino acid analyser (Jeolco, Tokyo, Japan). Tryptophan was determined by procedure C of Miller (1967). Amino acid analyses were carried out on whole milk and for the acid hydrolyses a large excess of 6 M-HC1 (1 ml/mg crude protein (CP)) was used to minimize destruction of amino acids due to carbohydrates and other organic constituents (Bigwood, 1960;Lindquist, 1966).

SUMMARYA study of the content of water soluble vitamins in the 12 baby milk formulae available in the UK in April 1983 showed that levels of vitamins in the individual brands were generally in excess of those declared by the manufacturer. For cows' milk based formulae the mean excess of vitamins over the declared level was 94%. Vitamin levels in prepared formulae averaged three times the minimum recommended level. The average level of B vitamins in prepared cows' milk based formulae was six times higher than in mature human milk. For the two soya based products, the levels of vitamins were generally in excess of the declared level and levels of vitamin B12, biotin and, in one sample, vitamin B6 were considerably in excess of those found in mature human milk.

Commercially pasteurized, non‐homogenized full cream milk in 2‐pt white polyethylene (PE)‐coated cartons overprinted with blue, and in 4‐pt PE bottles was stored for 4 d in the dark or under white fluorescent light of 4000 1x, at a temperature of 7°C. The flavour of milks kept in the dark remained good, but exposure to light resulted in early off‐flavour development: cartoned milk was disliked by a flavour panel after about 17.5 h exposure and milk in the PE bottles after 9 h. Vitamins A and B2 were stable in the milk during 4 d storage in the dark in both bottles and cartons, and in cartons exposed to light. In the bottled milks, light‐induced losses of these vitamins after 4 d were, respectively, 15% and 35%. but there was little or no loss before the development of light‐induced flavour. Loss of total vitamin C by day 4 was about 50% in the dark, irrespective of container. In the cartons exposed to light, 66% of the vitamin C was lost, while virtually none remained in the exposed, bottled milk. There was also a markedly greater loss of vitamin C in the bottled milk than in the cartoned milk at the time the flavour became unacceptable. The dissolved O2 concentration dropped considerably in the bottled milk exposed to light, but only marginally in the cartons. There were small increases in dissolved O2 in the dark in both types of container.

A survey was undertaken to update and extend available information on the vitamin content of pasteurized milk as produced at processing dairies in mainland UK and to investigate regional, seasonal and breed effects. The concentration of total retinol in milk from non-Channel Island (NCI) breeds averaged 619/tg/lOOg in summer and 41-2/£g/100g in winter. Concentrations of /^-carotene were 31*5 and 105/tg/100 g in summer and winter respectively. Concentrations of retinol in milk from Channel Island (CI) breeds were similar, but concentrations of /^-carotene were on average 3 times higher. The concentration of vitamin D 3 in milk from NCI breeds was 0-033/ig/100 g in summer and 0026 /ig/100 g in winter. There was no marked seasonal variation in the mean concentration of total vitamin C (14-5 /*g/ml). Values for the concentration of B vitamins (/jg/ml) were: folic acid 0-060, vitamin B 12 0'0042, riboflavin 1-78, nicotinic acid 0-71, pantothenic acid 3-60, biotin 0-020, thiamin 0-46 and vitamin B 6 061. Seasonal variation in the concentration was most marked for folic acid (c.v. 17-4%) and to a lesser extent for vitamin B 12 (c.v. 10-3%). The only breed differences in the B vitamin content were for riboflavin and folic acid, the mean values obtained for milk from CI breeds being respectively 20 and 10 % higher than those from NCI breeds.Because of its high nutritive value and the quantities consumed, milk is one of the most important primary commodities in the British diet. In addition to protein, fat, carbohydrate and Ca, milk is also a significant source of many vitamins and trace elements.Although monthly averages of butterfat and solids-not-fat in raw milk are published by the Milk Marketing Board, no recent comprehensive data on the nutrient content of pasteurized bulk milk from the British herd are available. In the most recent edition of Composition of Foods (Paul & Southgate, 1978) all values, apart from riboflavin, vitamin C and most minerals (analysed in bottled milk by the * Present address: Academia Medyczna, Zaklad Bromatologii,