Distribution and Resistance to Pasteurization of Aflatoxin M1 in Naturally Contaminated Whole Milk, Cream and Skim Milk

1983 ◽  
Vol 46 (6) ◽  
pp. 530-532 ◽  
Author(s):  
DANA W. WISEMAN ◽  
RHONÁS. APPLEBAUM ◽  
ROBERT E. BRACKETT ◽  
ELMER H. MARTH
Keyword(s):  
Heat Treatment ◽  
Skim Milk ◽  
Aflatoxin M1 ◽  
Whole Milk

Milk, naturally contaminated with aflatoxin M1 (AFM1) was separated with a hand-operated separator. Distribution of AFM1 paralleled the partitioning of whole milk into cream and skim milk. Most of the whole milk was recovered as skim milk, which also contained most of the AFM1. Cream accounted for 5–15% of the amount of whole milk and had 2–14% of AFM1 that originally occurred in whole milk. Cream and skim milk were pasteurized at 64°C for 30 min, AFM1 was stable in both products given this heat treatment.

Heat Resistance of Escherichia coli in Cow and Buffalo Milk

1980 ◽  
Vol 43 (5) ◽  
pp. 376-380 ◽  
Author(s):  
R. S. SINGH ◽  
B. RANGANATHAN
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Heat Resistance ◽  
Skim Milk ◽  
Buffalo Milk ◽  
Time Interval ◽  
E Coli ◽  
Heat Resistant ◽  
Whole Milk

Three Escherichia coli cultures (0111:B4, 0127:B8 and NP) were selected to study their heat-resistant characteristics when in cow skim, cow whole and buffalo whole milk. The temperatures of heat-treatment included in this study were 50, 55, 60 and 63 C. The time interval during heat-treatment was 10 min at 50 and 55 C and 5 min at 60 and 63 C. Marked differences in heat-resistance were observed in the three E. coli cultures. The z-values obtained for strain 0111:B4 were 8.3, 9.0 and 10.2 when tested in cow skim milk, cow whole milk and buffalo milk, respectively. The z-values for 0127:B8 and NP were 17.5, 18.0 and 19.2 and 18.8, 19.0 and 20.3, respectively, for the three types of milk.

Interactive Effects of Duration of Storage and Addition of Formaldehyde on Levels of Aflatoxin M1 in Milk

1988 ◽  
Vol 71 (2) ◽  
pp. 285-287 ◽  
Author(s):  
Susan K Heimbecher ◽  
Karen V Jorgensen ◽  
Ralph L Price
Keyword(s):  
Skim Milk ◽  
Raw Milk ◽  
Final Concentration ◽  
Interactive Effects ◽  
Aflatoxin M1 ◽  
Formaldehyde Concentration ◽  
Glass Containers ◽  
Whole Milk ◽  
Duration Of Storage ◽  
Spray Dried

Abstract Spray-dried skim milk, naturally contaminated with aflatoxin M„ was added to either raw or pasteurized whole milk to a final concentration of 1.1 Mg aflatoxin M,/L milk. Formalin (37% w/w) was added to the milk solutions to final concentrations of 0, 0.025, 0.05, and 0.1% formaldehyde. Samples were stored in the dark at 21°C in plastic and glass containers and were analyzed for aflatoxin M, at 0,1, 2, 3, and 4 weeks. This experiment was repeated using only raw milk and glass containers. Aflatoxin M, analyses were done at 0, 1, and 2 weeks. Aflatoxin M, losses increased over time and with increased formaldehyde concentration. With both experiments, aflatoxin M, levels after 2 weeks were less than 0.05 iigfL in samples containing 0.1% formaldehyde.

Thermal inactivation of γ-glutamyltranspeptidase and Enterococcus faecium in milk-based systems

1994 ◽  
Vol 61 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Shailam S. Patel ◽  
R. Andrew Wilbey
Keyword(s):  
Heat Treatment ◽  
Enterococcus Faecium ◽  
Thermal Inactivation ◽  
Skim Milk ◽  
Pilot Scale ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Whole Milk ◽  
Before And After ◽  
Enzymic Assay

SummaryUntreated whole milk, skim milk, sweetened milks, sweetened and unsweetened creams and ice-cream mixes were preincubated with a culture of Enterococcus faecium, then subjected to heat treatment in a pilot-scale plate heat exchanger using a hold of 15 s at 76°C. The liquids were examined for γ-glutamyltranspeptidase (GGTP) activity and total streptococcal count before and after heat treatment and the results plotted against water activity (aw). There was a good correlation between reduction in GGTP activity, destruction of streptococci and aw, demonstrating the potential of the enzymic assay for assessing the severity of HTST heat treatments above the minimum for pasteurization.

Effect of pH on the formation of deposit from milk on heated surfaces during ultra high temperature processing

1986 ◽  
Vol 53 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Paul J. Skudder ◽  
Brian E. Brooker ◽  
Andrew D. Bonsey ◽  
Norman R. Alvarez-Guerrero
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Skim Milk ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Concentration ◽  
Deposit Formation ◽  
Effect Of Ph ◽  
Whole Milk ◽  
Ultra High Temperature

SUMMARYInvestigation of the effect of pH on the formation of deposit from milk during ultra high temperature treatment using a plate-type plant showed that deposit formation was greatly increased when the pH of whole milk was reduced to 6·54, irrespective of whether the adjustment was made through the addition of HCl or lactic acid. Most of the increase in deposition took place in the higher temperature sections of the plant. Conversely, an increase in milk pH to 6·8 using NaOH resulted in considerably less deposit being formed during heat treatment. Reducing the pH of whole milk increased the deposition of both protein and fat, but reduced the deposition of minerals. Despite very high concentration of fat in the deposits, it is unlikely that fatper sewas responsible for increased deposit formation. Deposition also increased when the pH of skim milk was reduced to 6·51 before processing. Electron micrographs of the milks after heat treatment indicated that pH reductions caused the formation of large aggregates containing casein micelles during heating. Fat globules were also present in aggregates formed in whole milk with reduced pH. Slight reductions in the pH of milk before processing appear to enable the pH during heat treatment to fall below a critical value at which coagulation of milk takes place at the heated surfaces.

Chemical changes in bovine milk fat globule membrane caused by heat treatment and homogenization of whole milk

2002 ◽  
Vol 69 (4) ◽  
pp. 555-567 ◽  
Author(s):  
SUNG JE LEE ◽  
JOHN W. SHERBON
Keyword(s):  
Heat Treatment ◽  
Membrane Proteins ◽  
Milk Fat ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Chemical Changes ◽  
Milk Fat Globule Membrane ◽  
Whole Milk ◽  
Milk Fat Globule ◽  
Fat Globule

The effects of heat treatment and homogenization of whole milk on chemical changes in the milk fat globule membrane (MFGM) were investigated. Heating at 80 °C for 3–18 min caused an incorporation of whey proteins, especially β-lactoglobulin (β-lg), into MFGM, thus increasing the protein content of the membrane and decreasing the lipid. SDS-PAGE showed that membrane glycoproteins, such as PAS-6 and PAS-7, had disappeared or were weakly stained in the gel due to heating of the milk. Heating also decreased free sulphydryl (SH) groups in the MFGM and increased disulphide (SS) groups, suggesting that incorporation of β-lg might be due to association with membrane proteins via disulphide bonds. In contrast, homogenization caused an adsorption of caseins to the MFGM but no binding of whey proteins to the MFGM without heating. Binding of caseins and whey proteins and loss of membrane proteins were not significantly different between milk samples that were homogenized before and after heating. Viscosity of whole milk was increased when milk was treated with both homogenization and heating.

scholarly journals Rapid Determination of Ampicillin in Bovine Milk by Liquid Chromatography with Fluorescence Detection

1997 ◽  
Vol 80 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Catharina Y W Ang ◽  
Luo Wenhong
Keyword(s):  
Fluorescence Detection ◽  
Rapid Determination ◽  
Bovine Milk ◽  
Skim Milk ◽  
Reversed Phase ◽  
Coefficients Of Variation ◽  
Whole Milk ◽  
Liquid Chromatographic ◽  
Clear Supernatant

Abstract A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of am- picillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deprote- inized with trichloroacetic acid (TCA) and acetonitrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5,10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb.

Role of single serving form of dairy on satiety and postprandial glycaemia in young and older healthy adults

2019 ◽  
Vol 44 (12) ◽  
pp. 1289-1296 ◽  
Author(s):  
Shirley Vien ◽  
Hrvoje Fabek ◽  
Yurie Yamagishi ◽  
Ying Ti Lee ◽  
Bohdan L. Luhovyy ◽  
...  
Keyword(s):  
Older Adults ◽  
Blood Glucose ◽  
Milk Fat ◽  
Skim Milk ◽  
Area Under The Curve ◽  
Post Treatment ◽  
Dairy Proteins ◽  
Postprandial Glycaemia ◽  
Whole Milk

Dairy proteins reduce appetite and improve postprandial glycaemic response in adults. However, there are no reports of dairy in amounts usually consumed on satiety and postprandial glycaemia in either young or older adults. In a randomized crossover design, 30 healthy young adults (age: 23.5 ± 0.5 years; body mass index (BMI): 21.8 ± 0.4 kg/m2) and 30 healthy/overweight older adults (age: 65.2 ± 0.5 years; BMI: 24.7 ± 0.6 kg/m2) consumed 1 serving (according to manufacturers’ labels) of skim milk (0.1% milk fat (MF)), whole milk (3.25% MF), plain Greek yogurt (2% MF), cheddar cheese (31% MF), and water (energy-free control) after a 12-h fast. Subjective appetite was measured every 15–30 min over 3 h. Blood glucose and insulin were measured at baseline and every 15–30 min over 2 h. All dairy treatments reduced post-treatment subjective appetite area under the curve (AUC) over 3 h by 8%–17% more than water. Greek yogurt reduced appetite 3-h AUC more than skim and whole milk by 9% and 7%, respectively (p < 0.0001). Post-treatment blood glucose 2-h AUC was 42% lower in young compared with older adults (p = 0.003). It was also 52%–78% lower after cheese compared with milks and yogurt (p < 0.0001). Post-treatment insulin AUC after cheese was only 10%–15% of that after milks and Greek yogurt (p < 0.0001). We conclude that single servings of dairy differ in effect on postprandial satiety and glycaemia and merit consideration in management of metabolic syndrome.

Oxidation of Cholesterol in Commercially Processed Cow's Milk

1987 ◽  
Vol 50 (10) ◽  
pp. 867-871 ◽  
Author(s):  
MAE Z. CLEVELAND ◽  
NATHOLYN D. HARRIS
Keyword(s):  
Skim Milk ◽  
Milk Lipid ◽  
Oxidized Cholesterol ◽  
Heated Milk ◽  
Whole Milk ◽  
Dry Milk ◽  
Liquid Milk ◽  
Milk Lipids ◽  
And Storage ◽  
Layer Chromatography

Pasteurized whole milk, ultra-high temperature heated milk, canned evaporated milk, skim milk and instant nonfat dry milk were analyzed for presence of oxidized cholesterol compounds. Effects of heating whole milk and storage of whole milk lipid extracts were also examined. Analytical thin-layer chromatography data indicate that cholesterol in liquid milk was stable during commercial pasteurization, sterilization and evaporation. However, instant non-fat dry milk contained 7-hydroxy-cholesterol. Heating whole milk for 12 h at 85°C did not produce oxysterols, but GC-MS analysis indicate that storage of whole milk lipids may have produced steroidal ketones.

Survival of Borrelia burgdorferi in Whole Milk, Low Fat Milk, and Skim Milk at 34°C and in Skim Milk at 5°C

1991 ◽  
Vol 54 (7) ◽  
pp. 532-536 ◽  
Author(s):  
GERALDINE M. FARRELL ◽  
AHMED E. YOUSEF ◽  
ELMER H. MARTH
Keyword(s):  
Borrelia Burgdorferi ◽  
Milk Protein ◽  
Skim Milk ◽  
Storage Period ◽  
Most Probable Number ◽  
Low Fat ◽  
Probable Number ◽  
Whole Milk ◽  
The Mean ◽  
D Values

Autoclaved whole milk, low-fat milk, protein-fortified skim milk and regular skim milk were inoculated to contain ca. 105 to 106 Borrelia burgdorferi strains 35210, 35211, or EBNI/ml and stored at 34°C for 16 d. Similarly inoculated skim milk also was held at 5°C for 46 d. Numbers of survivors were estimated by the Most Probable Number (MPN) technique. In all instances, numbers of B. burgdorferi decreased over the storage period. At 34°C, no strain of B. burgdorferi was detected after day 12. The mean D-values, at 34°C, for strains 35210, 35211, and EBNI were 2.2, 2.4, and 2.2 d, respectively. The mean D-values, at 34°C, for all strains in whole milk, low-fat milk, protein-fortified skim milk, and regular skim milk were 2.4, 2.3, 1.9, and 2.4 d, respectively. At 5°C, spirochete numbers in regular skim milk decreased, but all three strains remained at a detectable level for 46 d. The mean D-values, at 5°C, for strains 35210, 35211, and EBNI were 12, 15, and 12 d, respectively.

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