Determination of mineral contents in different kinds of milk and estimation of dietary intake in infants.

Concentrations of 11 minerals were determined in six kinds of milk (cow's milk-based formulae, breast-milk, soya milk, bottled milk, dried milk and evaporated milk). The contents of copper, magnesium, molybdenum, aluminium, barium and nickel were higher in soya milk than in any other kinds of milk. Except for nickel in soya milk, the dietary intakes of minerals were below or close to the intake recommended by the FAO/WHO.     

Aluminium levels in Canadian infant formulate and estimation of aluminium intakes from formulae by infants 0-3 months old

Aluminium was determined in 282 cans of infant formulae and evaporated milks sold in Canada using graphite furnace atomic absorption spectrometry. Milk-based formulae contained average (range) concentrations of 0.129 (0.010-0.36), 0.217 (0.17-0.56) and 0.717 (0.19-2.49) micrograms/g ('as sold') in ready-to-use, concentrated liquid and powder formulae, respectively. The corresponding concentrations in the soy-based formulae were 1.98 (0.40-6.4), 1.41 (0.59-2.29) and 9.44 (3.15-18.0) micrograms/g. Evaporated milk contained 0.093 (0.022-0.34) micrograms/g. The levels varied extensively according to formula brand; e.g. for ready-to-use formulae, the range of average concentrations by formula brand were 0.42-3.28 micrograms/g for soy-based and 0.020-0.22 micrograms/g for milk-based products. Estimated aluminium ingestion from formula or milk by infants up to 3 months old ranged from 0.5 microgram per kg body weight per day (microgram/kg/day) or 2 micrograms/day for 0-1 month olds fed cow milk exclusively to 219 micrograms/kg/day (1260 micrograms/day) for 1-3 month olds fed only soy-based formulae. Consumption of only the formulae brand having the highest mean aluminium level (3.28 micrograms/g) by 1-3 month old infants could result in an intake of 363 micrograms/kg/day (2088 micrograms/day). The estimates assume that the sole source of aluminium is the formula or milk and do not include any potential contribution from other foods or water.     

The aluminium content of infant formula and tea

Tea and infant formulae have been examined for the presence of aluminium. Concentrations in 13 different tea infusions ranged from 2.2 mg/l to 4.5 mg/l. In cow's milk-based infant formulae as made up for consumption, aluminium levels of between 0.03 mg/l and 0.20 mg/l were detected. Higher amounts were present in soya-based formulae with concentrations ranging from 0.64 mg/l to 1.34 mg/l.     

Nutrient content of milk and milk products: water soluble vitamins in baby milk formulae

A 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.     

Aluminium content of Spanish infant formula

Levels of aluminium in 82 different infant formulae from nine different manufacturers in Spain were determined by acid-microwave digestion and graphite furnace atomic absorption spectrophotometry. The influence of aluminium content in tap water in reconstituted powder formulae was examined and an estimate was made of the theoretical toxic aluminium intake in comparison with the provisional tolerable weekly intake (PTWI). Possible interactions between aluminium and certain essential trace elements added to infant formulations have been studied according to the type or main protein-based infant formula. In general, the infant formulae contained a higher aluminium content than that found in human milk, especially in the case of soya, preterm or hydrolysed casein-based formulae. Standard formulae gave lower aluminium intakes amounting to about 4% PTWI. Specialized and preterm formulae resulted in a moderate intake (11-12 and 8-10% PTWI, respectively) and soya formulae contributed the highest intake (15% PTWI). Aluminium exposure from drinking water used for powder formula reconstitution was not considered a potential risk. In accordance with the present state of knowledge about aluminium toxicity, it seems prudent to call for continued efforts to standardize routine quality control and reduce aluminium levels in infant formula as well as to keep the aluminium concentration under 300 μg l^-1 for all infant formulae, most specifically those formulae for premature and low birth neonates.     

Nutrient content of milk and milk products: vitamins of the B complex and vitamin C in retail market milk and milk products

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.     

Determination of nitrates in milk by ion-chromatography

A method is described for the determination of nitrates in cow milk, human milk, milk powder or milk-based infant formulae using liquid chromatography on Spheron DEAE and a direct photometric detection (205 nm). The influence of removing proteins by precipitation with Carrez reagent on the accuracy of determination was studied. The proposed method gives identical results with the reference method (photometry after reduction of nitrate to nitrite) but is more rapid. Its limit of determination is 0.5 mg NO3-/l of milk, its reproducibility is 4% (relative standard deviation).     

Trace elements and their distribution in protein fractions of camel milk in comparison to other commonly consumed milks.

Studies on camels' milk, whether with respect to concentration or bioavailability of trace elements from this milk, are limited and warrant further investigation. The object of this study was to analyse the concentration and distribution of zinc, copper, selenium, manganese and iron in camel milk compared to those in human milk, cows' milk and infant formula under similar experimental conditions. Camels' milk and cows' milk were collected from local farms, human milk samples were obtained from healthy donors in Kuwait and infant formula was purchased locally. Milk fractionation was performed by ultra-centrifugation and gelcolumn chromatography. The concentration of trace elements was analysed by atomic absorption spectrometry and that of protein was determined spectrophotometrically. The concentration of manganese and iron in camels' milk was remarkably higher (7-20-fold and 4-10-fold, respectively) than in human milk, cows' milk and infant formula. The zinc content of camels' milk was higher than that of human milk but slightly lower than in cows' milk and infant formula. The concentration of copper in camels' milk was similar to that of cows' milk but lower than in human milk and infant formula. The selenium content of camels' milk was comparable to those of other types of milk, Approximately 50-80% of zinc, copper and manganese in camels' milk were associated with the casein fraction, similar to that of cows' milk, The majority of selenium and iron in camels' milk was in association with the low molecular weight fraction, It is recommended that camels' milk be considered as a potential source of manganese, selenium and iron, perhaps not only for infants, but also for other groups suspected of mild deficiency of these elements. Further investigations are required to confirm this proposal.     

Hunter versus CIE color measurement systems for analysis of milk-based beverages

The objective of our work was to determine the differences in sensitivity of Hunter and International Commission on Illumination (CIE) methods at 2 different viewer angles (2 and 10°) for measurement of whiteness, red/green, and blue/yellow color of milk-based beverages over a range of composition. Sixty combinations of milk-based beverages were formulated (2 replicates) with a range of fat level from 0.2 to 2%, true protein level from 3 to 5%, and casein as a percent of true protein from 5 to 80% to provide a wide range of milk-based beverage color. In addition, commercial skim, 1 and 2% fat high-temperature, short-time pasteurized fluid milks were analyzed. All beverage formulations were HTST pasteurized and cooled to 4°C before analysis. Color measurement viewer angle (2 vs. 10°) had very little effect on objective color measures of milk-based beverages with a wide range of composition for either the Hunter or CIE color measurement system. Temperature (4, 20, and 50°C) of color measurement had a large effect on the results of color measurement in both the Hunter and CIE measurement systems. The effect of milk beverage temperature on color measurement results was the largest for skim milk and the least for 2% fat milk. This highlights the need for proper control of beverage serving temperature for sensory panel analysis of milk-based beverages with very low fat content and for control of milk temperature when doing objective color analysis for quality control in manufacture of milk-based beverages. The Hunter system of color measurement was more sensitive to differences in whiteness among milk-based beverages than the CIE system, whereas the CIE system was much more sensitive to differences in yellowness among milk-based beverages. There was little difference between the Hunter and CIE system in sensitivity to green/red color of milk-based beverages. In defining milk-based beverage product specifications for objective color measures for dairy product manufacturers, the viewer angle, color measurement system (CIE vs. Hunter), and sample measurement temperature should be specified along with type of illuminant.     

Structures of the triglycerides of cows' milk, fortified milks (including. infant formulae), and human milk

The positional distributions of fatty acids in triglycerides from cows' milk, cows' milk enriched in linoleic acid by dietary means, and two commercial infant formulae fortified with vegetable fats have been determined for comparison with human milk. The results are discussed in terms of the digestibility of the fats and of the requirements of the human infant for linoleic acid .     

Effects of ammoniation on the 'carry-over' of aflatoxins into bovine milk

Two experiments were performed using lactating cows fed various treated and non-treated commodities from AFB1 contaminated peanut cakes. Treatment with ammonia gas by an autoclaving process was used for detoxification. Two methods were used for AFM1 determination in every milk sample: a TLC procedure recognized by AOAC and IDF and an HPLC method with a detection limit of 0.100 and 0.010 microgram/l, respectively. In a first experiment, lactating cows were fed treated and untreated meals during periods separated by uncontaminated soya meals phases. The total excreted AFM1 was 2.6% of the total ingested AFB1 from untreated feed contaminated at 1100 micrograms/kg. During periods receiving treated meals in the diet, AFM1 contents in milk were below 0.1 microgram/l. However, by using AFM1 data obtained using the HPLC method, an AFM1/AFB1 ratio of 4.6% was found from treated feed contaminated at 40 micrograms AFB1/kg. In a second experiment, a herd of 50 lactating cows was used for a long term (16 months) feeding of mixed commodities containing 30% ammoniated peanut cakes. AFB1 residues in the treated diet were below 10 micrograms/kg, the EEC action level, and no AFM1 residue was found up to 0.1 microgram/l in collected milk throughout this experiment.     

Analysis of Norwegian milk and infant formulas for ochratoxin A

Samples of organic cow's milk, conventional cow's milk, and cow's milk-based infant formulas were analysed for the occurrence of ochratoxin A by means of an HPLC method. The detection limit was 10ng/l. Ochratoxin A was detected in 6 out of 40 conventional cow's milk samples (range 11-58ng/l) , and in 5 out of 47 organic milk samples (range 15-28ng/l) . No ochratoxin A was detected in any of the 20 infant formula samples. The ochratoxin A levels in cow's milk found in this investigation are sufficient to cause a higher intake of ochratoxin A than the suggested TDI of 5ng/kg bw/ day, e.g. in small children who consume large quantities of milk.     

Lead, cadmium and aluminum in Canadian infant formulae, oral electrolytes and glucose solutions

Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant formulae, oral electrolytes and 5% glucose solutions available in Canada. In the electrolytes, Cd and Pb concentrations were all below 0.01 and 0.041 ng g(-1), respectively. In the 5% glucose solutions, Pb and Cd levels averaged 0.01 and 0.09 ng g(-1), respectively. Reported on an as-consumed basis, Pb levels in milk- and soya-based formulae averaged 0.90 and 1.45 ng g(-1), respectively, while Cd levels averaged 0.23 and 1.18 ng g(-1), respectively Average Al levels on an as-consumed basis were 440 ng g(-1) (range 10-3400 ng g(-1)) in milk-based formulae and 730 ng g(-1) (range 230-1100 ng g(-1)) in soy-based formulae. Al concentrations increased in the following order: plain formula < low-iron formula < iron-supplemented formula < casein hydrolysate formula ≈ premature formula ≤ soy formula. For example, in the powdered formulae, average Al concentrations were 18 ng g(-1) for plain milk-based, 37 ng g(-1) for low-iron, 128 ng g(-1) for iron supplemented, 462 ng g(-1) for lactose-free, 518 ng g(-1) for hypoallergenic and 619 ng g(-1) for soy-based formula. Al concentrations, as-consumed, increased with decreasing levels of concentration: powder < concentrated liquid < ready-to-use. Formulae stored in glass bottles contained between 100 and 300 ng g(-1) more Al than the same formulae stored in cans. The source of the increased Al did not appear to be the glass itself, because most electrolytes and glucose solutions, also stored in glass, contained less than 8 ng g(-1) Al. Corresponding differences in Pb and Cd levels were not observed. Al concentrations varied substantially among manufacturers; however, all manufacturers were able to produce plain milk-based formulae containing less than 50 ng g(-1) Al, i.e. within the range of Al concentrations found in human milk. Next to soya-based and hypoallergenic formulae, premature formulae contained among the highest concentrations of Al, ranging 851-909 ng g(-1) from one manufacturer and 365-461 ng g(-1) from another.     

Effect of processing and food matrix on calcium and phosphorous bioavailability from milk-based fruit beverages in Caco-2 cells

Calcium and phosphorus bioavailability from different milk-based (whole milk, skimmed milk and soya milk) fruit beverages as affected by thermal treatment (TT) and high-pressure processing (HPP) was determined by means of the paired in vitro gastrointestinal digestion (solubility method)/Caco-2 cell model. Ca bioaccessibility was significantly higher in HPP (98.4% ± 1.6%) versus TT (91.3% ± 1.9%), but Ca bioavailability was equal in all different matrixes independently of the processing treatment used. HPP samples improved P bioaccessibility (98.7% ± 2.5% versus 87.3% ± 2.2%) and P bioavailability by Caco-2 cells versus TT samples—soya milk- and whole milk-based beverages being the samples with the highest bioavailability values (56.8% ± 1.3% and 40.1% ± 9.9% versus 15.0% ± 2.1% and 16.8% ± 2.8%, respectively). Therefore, HPP improves Ca and P bioaccessibility, and P bioavailability versus TT samples, and can be used as an alternative to TT in the manufacture of functional foods with improved nutritional value and health benefits.     

Effect of storage at 4 degrees C on the physicochemical and renneting properties of milk: a comparison of caprine, ovine and bovine milks

The effects of cold storage at 4 degrees C for 12, 24 and 48 h on the physicochemical characteristics and renneting properties of ewes', goats' and cows' milks were compared. The most important changes were observed in cows' milk. Soluble calcium concentrations were not affected in ewes' milk but were increased by 10% in cows' milk and 7% in goats' milk. More casein was dissociated on cooling cows' (+300%) than goats' (+100%) milk, and there was no change in soluble casein in ewes' milk. The coagulation characteristics of cows' milk were more impaired by cold storage than goats' or ewes' milks. Coagulation times increased by approximately 30% and whey draining capacity decreased by 40% after cows' milk was cooled, but there were no changes with ewes' milk and only a slight decrease in coagulation time with goats' milk. We propose an interpretation of these results based on the physicochemical properties of each type of milk.     

Fast biosensor immunoassays for the detection of cows' milk in the milk of ewes and goats

Two monoclonal antibodies (MAb) raised against bovine kappa-casein were developed and applied in an automated optical biosensor (Biacore 3000) to create easy and fast direct and inhibition biosensor immunoassays (BIA) for the detection of cows' milk in the milk of ewes and goats. With both assay formats, low limits of detection (<01%) and fast run times (around 5 min) were obtained. For sample preparation, milk was diluted in buffer (direct assay) or in an antibody-containing buffer (inhibition assay) only. For quantitative analysis, calibrants of cows' milk in ewes' or goats' milk were used. Advantages of the direct BIA are: the single reagent format (biosensor chip immobilized antibodies only); the use of small amounts of antibodies (2 microg for >350 tests); and the wide measurement range (0.1 to 10% cows' milk). Despite these advantages, the inhibition BIA (using kappa-casein immobilized on the chip) was preferred because of the possible application of non-purified Mab, the higher responses, the higher sensitivity at relevant low percentages of cows' milk and its robustness (>800 cycles per chip).     

A limited survey of retail apple and grape juices for the mycotoxin patulin

A retail survey (38 samples) of apple, grape and other juice-based products for the mycotoxin patulin has been carried out using HPLC analysis. Positive results were confirmed by GC-MS of the TMS derivative using chemical ionization selected ion monitoring. No grape juice or mixed juice product contained detectable patulin (limit 5 micrograms/l), nor did the majority (58%) of the apple juices. Low levels of patulin (in the range 5-10 micrograms/l) were present in six apple juices and the remaining four positive samples contained 16, 18, 30 and 56 micrograms/l.     

Selenium concentrations in soya based milks and infant formulae available in the United Kingdom

A simple hydride generation atomic absorption spectrometric method previously described for bovine infant formulae has been successfuly applied for the analysis of selenium in UK soya based milks and infant formulae. Levels reported for the first time ranged from 0.011 to 0.040 μg/g (wet wt) for soya milks and from 0.023 to 0.089 μg/g (dry wt) for soya isolate infant formulae. No matrix interferences were encountered and the mean recovery was 100.1%. These values exhibit variation between batches, hence routine QC analysis and fortification by manufacturers is recommended.     

Ribonuclease activity and isoenzymes in raw and processed cows' milk and infant formulas

Because of evidence of an immunologic role for ribonuclease II (E.C. 3.1.27.5) in mammals, its presence in milk was further characterized to provide a basis for study of possible contributions of its activity to the health of infants. Isoenzymes of ribonuclease II were quantitatively resolved from milk samples as small as 1 ml or less by chromatography on phosphocellulose. Three isoenzymes detected in bovine milk were the previously reported ribonucleases A and B and a form termed ribonuclease II-1. These isoenzymes were in the ratio of 70:30:1. Form II-1 was unique in its inability to hydrolyze polycytidylate. Bovine colostrum contained 10 to 15 times more ribonuclease II-1 than does milk and three times more total ribonuclease II per unit volume. Human milk contains about 1% the concentration of ribonuclease II found in cows' milk. Ribonuclease II activity in milk was quite stable in the acidic conditions of whey production and during low heat treatments. However, most of its enzymatic activity was lost with high heat treatments. No commercially manufactured milk-based or soybean-based infant formula assayed contained nearly as much ribonuclease activity as either human or bovine milk.     

Occurrence of Campylobacter in retail foods in Ireland

A surveillance study was carried out to determine the prevalence of Campylobacter in a range of retail foods purchased in three Irish cities over a 20-month period between March 2001 and October 2002. In total 2391 food samples were analysed during this period. Campylobacter was isolated from 444 raw chicken (49.9%), 33 turkey (37.5%) and 11 duck samples (45.8%). Lower isolation rates of 7/221 (3.2%), 10/197 (5.1%) and 31/262 (11.8%) were observed for raw beef, pork and lamb, respectively. One sample of pork paté from 120 samples analysed (0.8%) was Campylobacter-positive. A total of three shellfish samples (oysters) from 129 raw specimens examined (2.3%) were found to contain Campylobacter. Low prevalences of the organism (0.9%) were also isolated from fresh mushrooms. Of 62 raw bulk tank milk samples analysed, Campylobacter was recovered in a single sample (1.6%). Campylobacter was not detected in any of the comminuted pork puddings, prepared vegetables and salads, retail sandwiches or cheeses made from unpasteurised milk. In total, 543 Campylobacter were isolated from all of the food samples analysed, of which 453 (83.4%) were confirmed as Campylobacter jejuni and the remaining 90 (16.6%) as Campylobacter coli.