Liquid Milk Products Research Articles

5149 Randomized phase II trial of preoperative chemotherapy plus lapatinib, trastuzumab or both in HER2 positive breast cancer: results of the first step simon's design

It has been suggested that recall bias may explain the discrepant results between case-control and cohort studies on diet and the risk of breast cancer. Two control groups were used for this case-control study of 25 to 75-year-old breast cancer cases (n = 310). The first group consisted of population controls drawn from the Finnish National Population Register (n = 454). The second group consisted of women who were referred to the same examinations as were the cases because of clinical suspicion of breast disease but who were later diagnosed as healthy (referral controls; n = 506). Because the diagnosis was unknown at the time of interview, it was possible to assess by comparing the two control groups whether the self-reporting of diet changed under the threat of disease. Dietary habits were examined using a validated, self-administered food-frequency questionnaire. Premenopausal women misreported their consumption of liquid milk products, tea, and sugar. Reporting bias was also associated with the intake of fat and vitamins. Postmenopausal women misreported consumption of milk products. When recall bias was taken into consideration, milk was associated with increased risk of premenopausal breast cancer, whereas high consumption of poultry or high intake of monounsaturated fatty acids, n-3 fatty acids, n-6 fatty acids, and vitamin E were related to lower risk. The study suggested that oil, milk, cheese, coffee and beta-carotene may act as protective factors in postmenopausal women, whereas butter and cream may be risk factors for breast cancer. In summary, it is possible that some food items may be overreported or underreported under the threat of disease in health-conscious population. However, most of the results in this study were not modified by recall bias.

Effect of milk solids concentration on the pH, soluble calcium and soluble phosphate levels of milk during heating

When milk is processed to dairy products, the concentration of the milk and the temperature/time combinations to which the milk is exposed can be varied. For example, large differences in milk concentrations and temperature/time combinations are used in the manufacture of milk powder or the various concentrated liquid milk products. Although the milk salts, particularly the concentrations and equilibrium states of calcium and inorganic phosphate, are considered to be important in the stability and functionality of dairy products, there have been few studies on the mineral balance in concentrated milk systems and how this is affected by temperature changes. The objective of this study was to examine the effect of milk concentration (9.6–38.4% w/w total solids), temperature (20–80 °C) and time (0–60 min) on the pH and the concentrations of soluble calcium (Casol) and soluble inorganic phosphate (Psol). At any given temperature, the level of Casol and Psol, as mmol·kg−1, increased and the pH decreased as the milk concentration was increased. However, when measured as a percentage of the total, the level of Casol and Psol decreased as the milk concentration was increased. At any given milk concentration, the level of Casol, Psol and milk pH decreased within the first few minutes of heating, with little further change at longer heating times. For milk samples at each concentration, there was a strong correlation between the final Casol and the final Psol at all temperatures. At any particular milk concentration, there was a strong correlation between the final milk pH and the final Casol or the final Psol levels. These results indicate that substantial decreases in milk pH, Casol and Psol can occur at the temperatures milk will experience in common commercial processes, and the extent of the changes will be dependent on the milk concentration and the processing conditions.

Comparison of Salmonella species recovered from Irish liquid milk production holdings with temporal clinical veterinary isolates

The presence of microbiological hazards in foodstuffs including, Salmonella, form a major source of food-borne diseases in humans. In-line milk filters from 97 liquid milk production holdings in Cork, the largest dairy region in Ireland, were surveyed for the presence of Salmonella species at herd level over a 2-year period (September 2001-September 2003). Each dairy farm was visited 6 times at 4 monthly intervals (denoted by cycles A-F). Six of the 97 herds (6%) were positive. Ten isolates were detected based on culture methods. These included five (5%) Salmonella Typhimurium DT104, 4 (4%) Salmonella Dublin, and 1 (1%) Salmonella Agona from a total of 556 filters. During cycle C, in addition to the milk filters, a bulk tank milk (BTM) sample was procured from each dairy holding and analysed but no Salmonella were isolated. For comparison purposes a further 26 temporal veterinary clinical isolates (21 S. Typhimurium of varying phage type, and 5 S. Dublin) were procured from the Cork Veterinary Clinical Diagnostic Laboratory, Cork. The study collection showed resistance to one or more antimicrobial agents. During the study, Salmonella spp. were isolated from five of the herds prior to any clinical signs in the farm animals. Pulsed-field gel electrophoresis (PFGE) profiles indicated clonality among the isolates pre- and post-clinical illness. A phenotypic and genotypic database for Salmonella spp. has been developed and used for comparative purposes.

Investigation of the Lactosylation of Whey Proteins by Liquid Chromatography−Mass Spectrometry

Heat treatment of milk induces a reaction between the milk proteins and lactose, resulting in lactosylated protein species. The lactosylation of the two major whey proteins alpha-lactalbumin and beta-lactoglobulin was investigated by reversed phase liquid chromatography-mass spectrometry (LC-MS). Three sample series, consisting of aqueous model solutions of each whey protein separately and in mixture and whole milk, were heated for different time periods, and the progression of the lactosylation reaction was monitored. The observed degrees of lactosylation and the reaction kinetics showed that the lactosylation of beta-lactoglobulin was not influenced by the presence of other components, whereas the lactosylation of alpha-lactalbumin was enhanced in whole milk compared to the aqueous model systems. An in-depth evaluation of the LC-MS data yielded information regarding changes of physicochemical properties of the whey proteins upon lactosylation. Whereas retention time shifts indicated changes in hydrophobicity for both alpha-lactalbumin and beta-lactoglobulin, changes in the charge state distribution denoting conformational alterations were observed only for beta-lactoglobulin. The analysis of different liquid and solid milk products showed that the lactosylation patterns of the whey proteins can be used as indicators for the extent of heat treatment.

Effect of the protein addition on the structure of set style and stirred yoghurt with and without the use of transglutaminase

Yoghurt production in Chile is increasing. Dairy industry exportations grown 45% in the past 2003–2004 period. From the total liquid milk production a 20% is used in the yoghurt process. It is important to mention that yoghurt in Chile is produced without protein addition and that the main yoghurt variety in the Chilean market is stirred yoghurt. Therefore, is interesting to increase the yoghurt quality and to investigate new applicable technologies. Membrane process in yoghurt production is a new technology (use of UF concentration to increase the dry matter) and, in the other hand, transglutaminase (TG) has been used mainly in the meat and soybean industry and not in the dairy one. Therefore the effect of the ultrafiltrated (UF) concentrate and skim milk powder on the structure of set style and stirred yoghurt were analyzed with and without the use of microbial TG. The effects of UF concentrate and the use of TG were evaluated. 2. Results and discussion

Vitamin D fortification as public health policy: significant improvement in vitamin D status in young Finnish men

Vitamin D insufficiency is common in northern countries during wintertime. In Finland, after the recommendation by the Ministry of Social Affairs and Health, vitamin D has been added to liquid milk products and margarines from February 2003. We determined the effects of national policy on vitamin D fortification on vitamin D status among young Finnish men. A comparison before and after intervention with study population of 196 young Finnish men (18-28 years) was carried out. Serum 25-hydroxyvitamin D3 (25-OHD3) concentrations were determined with the OCTEIA enzymeimmunoassay by IDS (Immunodiagnostic Systems Limited, Bolden, UK) in January 2003 (n = 96) and in January 2004 (n = 100), nearly 1 year after national vitamin D fortification had started. The mean serum 25-OHD3 concentrations during the wintertime increased by 50% after implementation of the vitamin D fortification of dairy products. Correspondingly, the prevalence of vitamin D insufficiency (serum 25-OHD3 < 40 nmol/l) was decreased by 50% from 78% in January 2003 to 35% in January 2004. Our results demonstrate that national vitamin D fortification substantially improved the vitamin D status of young Finnish men. Still, a third remained vitamin D insufficient.

Enterocyte and M-Cell Transport of Native and Heat-Denatured Bovine β-Lactoglobulin: Significance of Heat Denaturation

The three-dimensional structure, digestibility, and immunological properties of bovine beta-lactoglobulin (beta-lg) are modified by heat treatments used in processing of liquid milk products. Because it is not known if such treatments also modify the intestinal transport properties of beta-lg, the transport of native and heat-denatured bovine beta-lg was investigated in experimental cell models using Caco-2 cells and M cells. Transport of beta-lg labeled with a fluorescent marker was followed with fluorometric measurements, electrophoretic analyses, and fluorescence microscopy. The data show that both cell types transported native beta-lg more efficiently than they did heat-denatured beta-lg. In addition, M cells transported native beta-lg more than Caco-2 cells. Transport of native and heat-denatured beta-lg was transcellular. The electrophoretic data also suggest that heat-denatured beta-lg may have degraded more than native beta-lg during the transport.

New Data for Cholesterol Contents in Meat, Fish, Milk, Eggs and Their Products Consumed in Finland

This study was undertaken to produce cholesterol data in order to update the Finnish National Food Composition Data Base. The sampling included meat, fish, milk, eggs and their products. Sample preparation by a direct saponification method was applied. The cholesterol contents were determined by gas chromatography (GC) using an internal standard method for quantification. In meat and sausages the cholesterol contents ranged from 45 to 84 mg/100 g and from 36 to 75 mg/100 g, respectively. In most fish species the cholesterol contents were slightly higher ranging from 49 to 92 mg/100 g and they did not correlate with the fat contents. The contents in liquid milk products correlated with their fat contents ranging from 6.2 (milk with 1.5% fat) to 77 mg/100 g (cream with 38% fat). The corresponding range for cheese was 33–82 mg/100 g. The mean cholesterol content of eggs was 366 mg/100 g. The results were generally in line with other results, which have been recently obtained. However, for meat and high-fat milk products our results were partly lower than those reported in some food composition tables. The study showed that food composition databases should be periodically updated, i.e., by applying the most recent analytical methods and taking into account changes in foods available for consumption.

Dairy technology on the turn of the millennium

In general, the incentive for developing new technologies is determined by a) the need for increased product safety, economy and protection of the environment for existing products; b) the demand of consumers and the market for new dairy products and for foods containing milk ingredients. Membrane technology for separation and concentration of milk offers possibilities in the manufacture of existing consumer products such as cheese, liquid and fermented milk products as well as for the preparation of tailor-made products. One of the emerging technologies is the use of ultra-high-pressure because of its marked influence on milk proteins including enzymes, on lipids and on microorganisms. As this is a very costly technology, its application within the dairy industry may, therefore, be limited to special products. Despite the fact that the manufacturing process for all fermented dairy products includes biological operations, the introduction of new biotechnological methods to transform milk ingredients, the production of specific metabolites and continuous fermentation processes will increasingly gain importance in dairy plants. Energy saving in dairy industry will remain an important task for the technologists of the future. The milk industry is facing increasing product competition. Consequently, the intensive co-operation between industry and basic research is vital.

Processing characteristics of milk constituents

AbstractMilk and dairy products are major components of the human diet in Western countries, providing about 30% of dietary proteins and lipids. The current annual production of milk is 560 x 106 tonnes, of which 85, 11, 2 and 2% are bovine, buffalo, caprine and ovine, respectively. Although some raw milk is still consumed, the vast majority of milk is processed to at least some extent. Liquid milk is a major food item in all developed dairying countries, representing 30% of total milk production. The remainder is processed into one of several thousand products, making dairy products the most diverse and flexible group of food products. The flexibility of milk as a raw material resides in the chemical and physico-chemical properties of its constituents, many of which are unique. The principal constituents of milk can be modified by enzymatic, chemical and/or physical methods, permitting the production of new products. However, the concentrations and properties of milk constituents are variable and hence the processability of milk and the properties of dairy products are inconsistent, although much of this variability can be eliminated by employing modern technology, which exploits certain features of milk constituents. Today, most milk is processed in very large, highly mechanised and automated factories, where consistency in processing properties is essential. The resulting products are distributed through large wholesale and retail outlets, where consistency is, again, paramount. Finally, today's consumers expect consistency. The consistency expected by the processor, distributor and consumer can be achieved only if the properties of milk constituents are understood at the molecular level.This communication will describe:The chemical and physico-chemical properties of the principal constituents of milk, i.e. lactose, lipids, proteins and salts,Variations in milk composition and in the properties of its constituents and the influence of dairy husbandry practices thereon,Exploitation and significance of the chemical and physico-chemical properties of milk constituents in the production and properties of the principal groups of dairy foods, i.e. liquid milk products, cheese, butter, fermented milks, functional milk proteins and lactose.Process modifications which may be used to overcome variations in the properties of milk constituents.

Feasibility study into the use of a micro-machined grating spectrometer to measure fat and protein content in liquid milk products

A study was undertaken to determine the feasibility of building a system capable of measuring the protein and fat content in dairy based samples. The system would be based upon a micro-spectrometer. Using Beers–Lambert law, spectral absorption changes due to protein and fat variation in dairy samples are obtained, over the spectral region 800 to 1100 nm. Samples representing a range of liquid milk products, manufactured in the dairy industry were fabricated. These samples spanned typical fat and protein ranges. Each sample after preparation, was chemically analysed using standard Mojennier and Kjeldahl tests, for fat and protein content. The optical set-up required to optimise the collection from the sample is discussed.

Diet and the Risk of Breast Cancer in a Case-Control Study: Does the Threat of Disease Have an Influence on Recall Bias?

It has been suggested that recall bias may explain the discrepant results between case-control and cohort studies on diet and the risk of breast cancer. Two control groups were used for this case-control study of 25 to 75-year-old breast cancer cases ( n = 310). The first group consisted of population controls drawn from the Finnish National Population Register ( n = 454). The second group consisted of women who were referred to the same examinations as were the cases because of clinical suspicion of breast disease but who were later diagnosed as healthy (referral controls; n = 506). Because the diagnosis was unknown at the time of interview, it was possible to assess by comparing the two control groups whether the self-reporting of diet changed under the threat of disease. Dietary habits were examined using a validated, self-administered food-frequency questionnaire. Premenopausal women misreported their consumption of liquid milk products, tea, and sugar. Reporting bias was also associated with the intake of fat and vitamins. Postmenopausal women misreported consumption of milk products. When recall bias was taken into consideration, milk was associated with increased risk of premenopausal breast cancer, whereas high consumption of poultry or high intake of monounsaturated fatty acids, n-3 fatty acids, n-6 fatty acids, and vitamin E were related to lower risk. The study suggested that oil, milk, cheese, coffee and beta-carotene may act as protective factors in postmenopausal women, whereas butter and cream may be risk factors for breast cancer. In summary, it is possible that some food items may be overreported or underreported under the threat of disease in health-conscious population. However, most of the results in this study were not modified by recall bias.

Analysis of Dairy Products by Near-Infrared Spectroscopy: A Review

Near-infrared spectroscopy analysis of foodstuffs is a relatively recent technique. Its principal advantage is speed of analysis, and it does not require sample pretreatment either. In this paper we review its application to powder dairy products, liquid milk, cheese, butter, and fermented milk products, mainly from the analysis of the major components point of view and also for the detection of adulterations and other determinations as well. Keywords: Near-infrared spectroscopy; dairy products

Enzymatic Determination of Lactose and Galactose in Foods: NMKL Collaborative Methods Performance Study

Abstract Enzymes are widely used in food chemistry as analytical tools. An enzymatic method for determining lactose and galactose in foods was evaluated in an interlaboratory methods performance study by 12 laboratories in 4 countries. The method is based on enzymatic hydrolysis of lactose and enzymatic oxidation of the hydrolysis products. The exchange of the coenzyme in the second reaction is the basis of quantitation. The method may be used for various types of foods, such as liquid and solid milk products, meat products, cereal products, fats, dressings, sweets, chocolate, and foods for special dietary uses. It is also applicable to lactose-free foods but not to products in which lactose has been partially hydrolyzed enzymatically to glucose and galactose. Six commonly used foodstuffs with lactose concentrations ranging from 0.4 g/100 g to 40 g/100 g and galactose concentrations up to 0.7 g/100 g were analyzed: crisp rye bread, milk chocolate, sausage, cheese, margarine, and baby food containing milk powder. They were distributed to the 12 participants as 12 randomly numbered test samples, representing blind duplicates of the 6 materials. The relative standard deviations for reproducibility (RSDR) were between 2.3-11% for lactose and 6.8-50% for galactose.

Tethering of grazing goats in tanzania: effect of tethering for 4 or 8 hours daily on intake and milk yield of norwegian cross local goats grazing brachiaria in the wet season

The experiment formed part of a development programme to improve tethering practice and increase liquid milk production from grazed goats on smallholder farms. A local survey in upland (Mgeta) and lowland (Mlali) districts near Morogoro (Sendalo, Mtenga, Ngapongora, Minde, Owen, Romney and Gill, 1994) indicated that goats were tethered at sites of grazing for 4 to 8 hours (h) daily (d), with the animals being housed, generally without additional feeding, at other times. The survey also indicated that tethering was a particularly common method of controlling grazing during the wet, crop-planting/crop growing period.The experiment therefore compared the milk production of lactating goats tethered to graze during the wet season for 4 or 8 h per day. An attempt was made to measure intake during grazing. The experiment tested the hypothesis that goats tethered to graze for 4 h/d would be unable to consume as much grass as those grazed for 8 h/d and consequently, would produce less milk.

Tethering of grazing goats in tanzania: effect of tethering for 4 or 8 hours daily on intake and milk yield of norwegian cross local goats grazing brachiaria in the wet season

The experiment formed part of a development programme to improve tethering practice and increase liquid milk production from grazed goats on smallholder farms. A local survey in upland (Mgeta) and lowland (Mlali) districts near Morogoro (Sendalo, Mtenga, Ngapongora, Minde, Owen, Romney and Gill, 1994) indicated that goats were tethered at sites of grazing for 4 to 8 hours (h) daily (d), with the animals being housed, generally without additional feeding, at other times. The survey also indicated that tethering was a particularly common method of controlling grazing during the wet, crop-planting/crop growing period.The experiment therefore compared the milk production of lactating goats tethered to graze during the wet season for 4 or 8 h per day. An attempt was made to measure intake during grazing. The experiment tested the hypothesis that goats tethered to graze for 4 h/d would be unable to consume as much grass as those grazed for 8 h/d and consequently, would produce less milk.

The spontaneously hypertensive rat's preference for salted foods

Sprague-Dawley rats drink mild salt (NaCl) solutions in preference to plain water. In contrast, rats of this strain are less likely to show preferences when salt is tested in food. Others have established that rats of the spontaneously hypertensive strain (SHR) have greater preferences for salt water than do their normotensive counterparts (WKY). The question addressed in the present research was whether SHR rats would show an enhanced salted food preference when compared with WKY rats. SHR and WKY rats were given choices between a variety of salted and unsalted foods. When tested with potato chips, no major strain differences in salt preferences were observed; depending on concentrations, rats ate either equal amounts of salted and unsalted chips or avoided salted chips. However, when tested with liquid milk products (heavy cream and half & half), SHR rats showed both higher salt preferences and consumed more salt. The SHR actually preferred these products salted, whereas the WKY rats, like Sprague-Dawley rats, never ate more salted milk than plain milk. When tested with skim milk, SHR and WKY did not differ; both preferred the milk salted. In order to test the effect of physical state (or texture) upon salt preference, the skim milk was gelled. Salt preferences of the SHR rats fell to 50% whereas the salt preferences of the WKY rats remained unchanged.

Salted food preferences in rats ( Rattus norvegicus): Responses to liquid milk products

Sprague-Dawley rats do not prefer salted (NaCl) solid food when it is presented with its unsalted counterpart but prefer isotonic saline when it is presented with plain water. Preferences in liquid foods were examined by giving rats one-hour choices between various salted liquid milk products and their unsalted counterparts. When heavy cream and half and half were tested, rats consumed either equal amounts of the salted and unsalted food, or more of the unsalted food. The absence of salt preference in heavy cream and half and half was evident using other testing procedures and, with heavy cream, additional salt concentrations. In contrast, rats consumed more skin milk containing 0.150 M NaCl than plain skim milk. The role of fat content in modulating the expression of these salt preferences was examined in tests using whole milk and low-fat milk, both of which have water, protein and carbohydrate contents similar to skim milk, but a greater fat content. Unlike skim milk, preferences for 0.150 M NaCl in whole milk and low-fat milk were approximately 50%. The role of solidity in salted food preferences was also investigated by adding gelatin to salted (0.150 M NaCl) and unsalted skim milk. Whereas the rats ate equal quantities of salted and unsalted gelled skim milk, they preferred salted skim milk when it was a liquid. Results from these experiments suggest that several cues contained within food influence the expression of rats' salt preferences.

Efficiency and performance of genetically high and low milk-producing British Friesian and Jersey cattle

ABSTRACTGenetic lines for high and low liquid milk production were established within the British Friesian and British Jersey breeds by random matings of experimental dams to the ‘best’ and ‘worst’ nationally available progeny-tested sires. Some Friesian dams could also be classified as either high or low for genetic potential for milk yield on the basis of previous, but less rigorously controlled, matings to high-or low-production sires. The dams and their high and low potential-production female progeny were reared indoors, and given a single complete pelleted diet ad libitum from weaning until leaving the experiment after their third calving. Height at withers and width at hooks were recorded monthly, cumulate food intake and body weight fortnightly and milk yield, fat and protein concentration weekly, throughout life in the experiment. Measures of lactation production, food intake and efficiency of conversion of food to milk product during the whole calving-to-calving interval were obtained. Yields were about 0-8 times national average yields. Differences between high and low genetic lines appeared similar for the two breeds. High potential-production progeny produced more liquid milk, fat and protein but at a lower fat and protein concentration than did low-potential progeny. High-potential progeny consumed more food from calving to calving and had higher food conversion efficiencies to liquid milk, fat and protein. The response in efficiency accompanying a given change in production was close to that predicted by phenotypic regression of efficiency on yield with a 0-75% increase in efficiency for every 1% increase in yield. The likelihood of smaller returns in efficiency at higher yields is discussed. High potential-production progeny lost more body weight than did low during lactation, suggesting a greater withdrawal of energy from body reserves. High-potential progeny were neither heavier nor taller but were marginally narrower at the hooks than were low-potential progeny, suggesting the possibility of increased calving difficulties as selection for increased yield continues.Friesians produced 50% more liquid milk, 13% more milk fat and 29% more milk protein and consumed 22% more food from calving to calving than did Jerseys. As a consequence Friesians were markedly more efficient at producing liquid milk (+23%) but essentially no more efficient at producing milk energy (+2%) than were Jerseys. In terms of both biological and commercial application of the results, any biases in the experiment probably operated against the Jersey relative to the Friesian.Predictions of food intake using accepted feeding standards underestimated observed total food intake during lactation by a factor of 0-8. Linear regression indicated underestimation of maintenance requirement as a likely explanation.

High Performance Liquid Chromatographic Analysis of Cholesterol in Milk

A method was developed for analysis of cholesterol in whole milk powder and commercial liquid milk products. High performance liquid chromatography employed a nonaqueous reversed phase chromatographic system. Sample preparation was by saponification with methanolic potassium hydroxide followed by extraction with ether. Potential interfering substances were removed prior to injection by a simple clean-up procedure using a silica gel Sep-pakTM, The chromatographic system included a carbon-18 column with a hexane/isopropanol mobile phase and detection at 205nm. Method validation and recovery studies using carbon–14 labeled cholesterol indicated excellent performance.