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Jones EW, Derrick J, Nisbet RM, Ludington WB, Sivak DA. First-passage-time statistics of growing microbial populations carry an imprint of initial conditions. Sci Rep 2023; 13:21340. [PMID: 38049502 PMCID: PMC10696051 DOI: 10.1038/s41598-023-48726-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/29/2023] [Indexed: 12/06/2023] Open
Abstract
In exponential population growth, variability in the timing of individual division events and environmental factors (including stochastic inoculation) compound to produce variable growth trajectories. In several stochastic models of exponential growth we show power-law relationships that relate variability in the time required to reach a threshold population size to growth rate and inoculum size. Population-growth experiments in E. coli and S. aureus with inoculum sizes ranging between 1 and 100 are consistent with these relationships. We quantify how noise accumulates over time, finding that it encodes-and can be used to deduce-information about the early growth rate of a population.
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Affiliation(s)
- Eric W Jones
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
| | - Joshua Derrick
- Department of Biological Sciences and Engineering, Carnegie Institution for Science, Baltimore, MD, 21218, USA
| | - Roger M Nisbet
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - William B Ludington
- Department of Biological Sciences and Engineering, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - David A Sivak
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
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Rasane P, Sharma N, Fatma S, Kaur S, Jha A, Kaur D, Singh J. Ultra-high Temperature (UHT) Processing: Technological Significance and Updates. CURRENT NUTRITION & FOOD SCIENCE 2020. [DOI: 10.2174/1573401316666200217111113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Background: Milk forms an integral part of the human diet from the nutritional point of
view. Besides nutrition, it has also unique functional properties which are harnessed by the industry
for numerous uses. Being highly perishable specific techniques are required to minimize the losses
during processing and adequate preservation of this precious commodity. In the U.S. and many other
parts of the world, the traditional pasteurization of milk requires a minimum heat treatment of 72ºC
for 15 seconds with subsequent refrigeration. However, the advent of Ultra High Temperature (UHT)
treatment of milk has added a new dimension to the marketing of liquid milk in urban as well as remote
areas without the requirement of cold chain management. The distinctive feature of UHT processed
milk is that it is commercially-sterile-not pasteurized and so has long shelf life at room temperature.
UHT milk, also known as long-life milk, is emerging as an attractive commercial alternative
offering a hygienic product of unmatched quality, which can be bought anywhere, at any time
and in any quantity. The present review will discuss numerous aspects of UHT processing of milk
with reference to historical significance, fundamental principle, various systems used and prerequisites,
type of exchangers used, fouling and other defects in system, chemical and microbiological effect
of the treatment, its effect on nutritional components, organoleptic quality of milk and the advantage
and involved challenges of the process.
Conclusion:
Raw milk is easily contaminated with pathogens and microbes and hence its consumption
of raw milk is associated with certain ill health effects. Therefore, heating milk before consumption
is strongly suggested. Thus, UHT treatment of milk is done to ensure microbial safety and also
to extend the shelf life of this highly perishable commodity. Heating milk at such a high temperature
is often associated with the change of organoleptic properties like change in flavor or cooked flavor,
rancidity due to microbes or acid flavor, etc. But UHT treatment does not substantially decrease the
nutritional value or any other benefits of milk.
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Affiliation(s)
- Prasad Rasane
- Department of Food Technology and Nutrition, Lovely Professional University, Punjab 144411, India
| | - Nitya Sharma
- Department of Farm Engineering, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India
| | - Sana Fatma
- Department of Dairy Science and Food Technology, Banaras Hindu University, Varanasi 221005, India
| | - Sawinder Kaur
- Department of Food Technology and Nutrition, Lovely Professional University, Punjab 144411, India
| | - Alok Jha
- Department of Dairy Science and Food Technology, Banaras Hindu University, Varanasi 221005, India
| | - Damanpreet Kaur
- Department of Food Technology and Nutrition, Lovely Professional University, Punjab 144411, India
| | - Jyoti Singh
- Department of Food Technology and Nutrition, Lovely Professional University, Punjab 144411, India
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Ahn SI, Lee YK, Kwak HS. Physicochemical and sensory properties of milk supplemented with lactase microcapsules coated with enteric coating materials. J Dairy Sci 2019; 102:6959-6970. [PMID: 31255265 DOI: 10.3168/jds.2018-15865] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/19/2019] [Indexed: 11/19/2022]
Abstract
In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (β-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.
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Affiliation(s)
- Sung-Il Ahn
- Department of Animal Science, Chonbuk National University, Jeonbuk, 54896, Korea
| | - Yun-Kyung Lee
- Department of Food and Nutrition, KyungHee University, Seoul, 02447, Korea
| | - Hae-Soo Kwak
- Department of Food Science and Technology, Sejong University, Seoul, 05006, Korea.
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López-Fandiño R, Olano A. Review: Selected indicators of the quality of thermal processed milk / Revisión: Indicadores seleccionados para el control de calidad de la leche tratada térmicamente. FOOD SCI TECHNOL INT 2016. [DOI: 10.1177/108201329900500202] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Selected indicators of the quality of processed milk are reviewed in three sections: indices of heat treatment, detection of adulterations and assessment of shelf life. The characterization of the thermal process to which milk was submitted can be achieved by measuring either the formation of new compounds (lactulose, furosine) or the degradation of thermolabile constituents (enzymes, whey proteins). The presence of certain compounds may indicate fraudulent additions committed for eco nomic reasons. Finally, residual or reactivated heat stable enzymes may cause serious storage defects in UHT milk and, therefore, the proteolytic and lipolytic activities and the degree of protein and lipid degradation are useful predictors of the shelf life. Different analytical methods for the determination of the selected quality indicators are also summarized.
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Affiliation(s)
- R. López-Fandiño
- Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - A. Olano
- Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
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Martin N, Carey N, Murphy S, Kent D, Bang J, Stubbs T, Wiedmann M, Dando R. Exposure of fluid milk to LED light negatively affects consumer perception and alters underlying sensory properties. J Dairy Sci 2016; 99:4309-4324. [DOI: 10.3168/jds.2015-9603] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 02/20/2016] [Indexed: 11/19/2022]
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Koushki M, Koohy-Kamaly P, Azizkhani M, Hadinia N. Microbiological quality of pasteurized milk on expiration date in Tehran, Iran. J Dairy Sci 2016; 99:1796-1801. [PMID: 26774719 DOI: 10.3168/jds.2015-10400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/20/2015] [Indexed: 11/19/2022]
Abstract
The aim of this study was to determine the microbiological quality of pasteurized milk on expiration date in Tehran. Two hundred fifty-four samples collected using a simple randomized sampling method from March 2014 to January 2015 were tested for total microbial count, coliform count, and Escherichia coli contamination according to Iran's National Standards methods. Total microbial count, coliform count, and E. coli contamination exceeded the standard limits in 61.1% [>7.5 × 10(4) (4.88 log) cfu/mL], 24.4% [>10 (1 log) cfu/mL], and 8.7% of the samples, respectively. The mean total microbial count [7.1 × 10(7) (7.85 log) cfu/mL] was above the standard limit. Only 36.6% of the studied samples were in accordance with Iran's National Standard limits. Based on our results, it is necessary to improve the microbial quality of pasteurized milk in Iran.
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Affiliation(s)
- Mohammadreza Koushki
- Research Department of Food Technology, Shahid Beheshti University of Medical Sciences, PO Box 19395-4741, Tehran, Iran
| | - Paliz Koohy-Kamaly
- Research Department of Food Technology, Shahid Beheshti University of Medical Sciences, PO Box 19395-4741, Tehran, Iran.
| | - Mohammad Azizkhani
- Students Research Committee, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, PO Box 19395-4741, Tehran, Iran
| | - Noushin Hadinia
- Students Research Committee, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, PO Box 19395-4741, Tehran, Iran
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Vijayakumar S, Grewell D, Annandarajah C, Benner L, Clark S. Quality characteristics and plasmin activity of thermosonicated skim milk and cream. J Dairy Sci 2015; 98:6678-91. [DOI: 10.3168/jds.2015-9429] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 06/13/2015] [Indexed: 11/19/2022]
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Abstract
SUMMARYFor milk from four herds of cows, maintained under different conditions of feeding and management, the natural Cu content and the stability of the ascorbate were highly correlated. Low Cu levels in milk from cows at pasture at farms A and B during the summer were associated with low storage losses of ascorbate. During this period, the milk of cows at farms C and D (on forage and Cu-supplemented concentrate) was richer in Cu, and losses of ascorbate were high. Heat treatment of the milk stabilized the ascorbate. Thus, in ‘high Cu’ milk (60 µg Cu/l), loss of ascorbate in the raw milk was 58% at 2 d, as against 17% after pasteurization at 72 °C and no loss after treatment at 82 °C. Storage of milk in light caused rapid destruction of ascorbate, equally with 72 and 82 °C heat treatments. The effects were examined of milk pasteurization temperature (72–82 °C) on flavour stability, bacteriological quality and vitamins of the B-complex. Heat treatment at 82 °C increased the susceptibility of vitamin B12to destruction by light, but otherwise caused no greater losses of B-complex vitamins than did treatment at 72 °C. Taste panel ratings showed an initial preference for milk heated at 72 °C, but on storage of this milk in darkness the flavour score fell progressively and at 5 d it was judged ‘stale’. Treatment at 82 °C gave a faint ‘cooked’ flavour although, unlike that of the 72 °C-treated milk, the flavour remained stable throughout 14-d storage and after d 8 was increasingly preferred. On exposure to light after treatment at 72 °C milks rapidly acquired an unpleasant‘oxidized’ flavour, but after treatment at 82 °C, exposure to light had no such adverse effect on flavour during the early days of storage. Pasteurization at ∼ 80 °C offers a potential for improvement in the oxidative stability of milk and its contribution of vitamin C to the diet.
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Abstract
SummaryEffect of heating and of some chemical treatments on the proteolysis of skim milk caused by its major proteinase system, plasmin, was investigated. Degree of proteolysis was expressed as the increase in γ-casein content of skim milk (mg/ml) after incubation with 0·02% (w/v) NaN3 at 37 °C for 20 h. Apart from reduced proteolysis in skim milk heated at > 70 °C for 10 min or at 75 °C for ∼ 5 min, some enhancement (10–80%) was observed on heating at 55–63 °C for 10 min or at 60–65 °C for 15 s. Heating at pasteurization conditions (63 °C/30 min or 72 °C/15 s) had no apparent effect on the amount of proteolysis. Addition of ascorbic acid (0·2 mg/100 ml) or H2O2 (1/100 ml) to unheated skim milk also increased the amount of proteolysis by 38 and 28%, respectively. However, the extent of this increase diminished with increasing amounts of both chemicals. Furthermore, there was a steady increase (∼ 33%) in proteolysis with time of exposure to light for up to 3 h. These results suggest that oxidative conditions lead skim milk to enhanced proteolysis by inactivating an inhibitor(s) operating in the plasmin system in milk.
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Gandy A, Schilling M, Coggins P, White C, Yoon Y, Kamadia V. The Effect of Pasteurization Temperature on Consumer Acceptability, Sensory Characteristics, Volatile Compound Composition, and Shelf-Life of Fluid Milk. J Dairy Sci 2008; 91:1769-77. [DOI: 10.3168/jds.2007-0833] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Papachristou C, Badeka A, Chouliara I, Kondyli E, Kourtis L, Kontominas MG. Evaluation of polyethylene terephthalate as a packaging material for premium quality whole pasteurized milk in Greece. Eur Food Res Technol 2006. [DOI: 10.1007/s00217-006-0398-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Papachristou C, Badeka A, Chouliara E, Kondyli E, Athanasoulas A, Kontominas MG. Evaluation of polyethylene terephthalate as a packaging material for premium quality whole pasteurized milk in Greece. Eur Food Res Technol 2006. [DOI: 10.1007/s00217-006-0280-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Moyssiadi T, Badeka A, Kondyli E, Vakirtzi T, Savvaidis I, Kontominas MG. Effect of light transmittance and oxygen permeability of various packaging materials on keeping quality of low fat pasteurized milk: chemical and sensorial aspects. Int Dairy J 2004. [DOI: 10.1016/j.idairyj.2003.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Vassila E, Badeka A, Kondyli E, Savvaidis I, Kontominas MG. Chemical and microbiological changes in fluid milk as affected by packaging conditions. Int Dairy J 2002. [DOI: 10.1016/s0958-6946(02)00065-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Simon M, Hansen AP. Effect of Various Dairy Packaging Materials on the Shelf Life and Flavor of Pasteurized Milk. J Dairy Sci 2001; 84:767-73. [PMID: 11352151 DOI: 10.3168/jds.s0022-0302(01)74532-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Milk from three different dairies (each a separate trial: 1, 2, and 3) was standardized to 2% fat and pasteurized at 92.2, 84.0, and 76.4 degrees C (temperatures 1, 2, and 3, respectively) for 25 s and packaged into six different packaging boards, [standard (A) milk boards with standard seam; juice boards with standard (B) and J-bottom (D) seams; barrier boards with standard (C) and J-bottom (E) seams; and foil (F) boards with J-bottom seam], resulting in 18 different treatments. Standard plate count (SPC) was used to test for microbial quality, and taste a panel was employed for flavor acceptability and difference on the milk stored at 6.7 degrees C at 1, 2, 3, and 4 wk. Statistical analysis of taste panel data showed that the flavor of milk samples A2, B2, and D2 deteriorated faster than the blind control (freshly high temperature, short time pasteurized low fat milk processed at 80.6 degrees C for 25 s). The flavor of milk packaged in standard (A) and juice (B and D) boards deteriorated at a faster rate than milk packaged in barrier (C and E) and foil (F) boards. Microbial counts showed that milk samples stored at 6.7 degrees C in trials 2 and 3 produced high SPC at wk 3 (ranges of bacteria in cfu/ml for trial 2: 9.9 x 10(1)-1.8 x 10(6) and trial 3: 2.5 x 10(5)-5.5 x 10(8)). In trial 1, high SPC began at wk 4 (9.9 x 10(1)-5.5 x 10(5) cfu/ml). Milk processed at 76.4 degrees C had the lowest bacterial growth rate, and milk processed at 84.0 degrees C had the highest bacterial growth rate. Different boards had no effects (P > 0.05) on the bacterial growth rates. It appeared that the lower the SPC of the raw milk, the slower the bacterial growth rate after 2 wk of storage. Milk samples stored at 1.7 degrees C maintained low SPC at wk 4, with counts of 0 to 40 cfu/ml for trial 2 and 0 to 200 cfu/ml for trial 3.
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Affiliation(s)
- M Simon
- North Carolina State University, Raleigh 27695, USA
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Ostdal H, Andersen HJ, Nielsen JH. Antioxidative activity of urate in bovine milk. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000; 48:5588-5592. [PMID: 11087523 DOI: 10.1021/jf000658w] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The antioxidative effects of urate on peroxidase-induced protein oxidation and light-induced riboflavin degradation and lipid oxidation in whole milk were studied. In addition, experiments using ascorbate were conducted to directly compare the antioxidative activity of urate and ascorbate. The presence of urate and/or ascorbate (10-30 mg/L) lowered peroxidase-induced formation of dityrosine by 44-96% in unpasteurized whole milk. No synergistic effect of urate and ascorbate on peroxidase-induced dityrosine formation was registered, but merely an additive effect. Light exposure of pasteurized whole milk showed that ascorbate was oxidized at the expense of urate, which indicated ascorbate-mediated recycling of the urate radical. Moreover, both urate and ascorbate (30 mg/L) retarded light-induced lipid oxidation in pasteurized whole milk as measured by formation of lipid hydroperoxides with urate being the most effective (28% reduction in lipid hydroperoxides) compared with ascorbate (14%). Finally, addition of urate or ascorbate (300 mg/L) to pasteurized whole milk showed a slight protective effect against light-induced degradation of riboflavin with urate being the most effective.
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Affiliation(s)
- H Ostdal
- Department of Animal Product Quality, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark.
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Erickson MC. Chemical and microbial stability of fluid milk in response to packaging and dispensing. INT J DAIRY TECHNOL 1997. [DOI: 10.1111/j.1471-0307.1997.tb01748.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Andersson I, Öste R. Nutritional quality of pasteurized milk. Vitamin B12, folate and ascorbic acid content during storage. Int Dairy J 1994. [DOI: 10.1016/0958-6946(94)90066-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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LAVIGNE C, ZEE J, SIMARD R, Béliveau B. Effect of Processing and Storage Conditions on the Fate of Vitamins B1, B2, and C and on the Shelf-Life of Goat's Milk. J Food Sci 1989. [DOI: 10.1111/j.1365-2621.1989.tb08560.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jenq W, Bassette R, Crang RE. Effects of Light and Copper Ions on Volatile Aldehydes of Milk and Milk Fractions. J Dairy Sci 1988. [DOI: 10.3168/jds.s0022-0302(88)79820-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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