scholarly journals Use of fluorometry for determination of skim milk powder adulteration in fresh milk

2005 ◽  
Vol 6B (11) ◽  
pp. 1101-1106 ◽  
Author(s):  
Rong-fa Guan ◽  
Dong-hong Liu ◽  
Xing-qian Ye ◽  
Kai Yang
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Fresh Milk

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Determination of Moisture by Mid Infrared Transmission Spectroscopy

1988 ◽  
Vol 71 (5) ◽  
pp. 1024-1027 ◽  
Author(s):  
Frederick R Van De Voort ◽  
Marilou Laureano ◽  
James P Smith
Keyword(s):  
Near Infrared ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Infrared Transmission ◽  
Mid Infrared ◽  
Standard Curve ◽  
Moisture Extraction ◽  
Infrared Method

Abstract An investigation was undertaken to determine whether commercially available mid infrared filter instrumentation (i.e., Multispec MK1) could be used to determine moisture in a manner similar to the AOAC near infrared method. Using a specially designed IR scanning spectrophotometer capable of working with aqueous systems, functional sample (6.02 jtm) and reference (5.56 iim) wavelengths were determined for quantitating water-methanol mixtures, and a standard curve was derived. Skim milk powder, bread crumbs, and flour were mixed with dry methanol to extract moisture into the solvent; moisture was quantitated relative to 3 AOAC methods. The results indicated that the wavelength pair selected worked well and had the potential to determine moisture content of low moisture food products, given that appropriate moisture extraction protocols were derived. This work indicates that the capabilities of commercial filter-based mid infrared instruments could be expanded to include moisture analyses if such instruments were equipped with the appropriate interference filters to carry out this determination.

Determination of Chloride in Infant Formula and Adult/Pediatric Nutritional Formula by Potentiometric Titration: Single-Laboratory Validation, First Action 2015.07

2016 ◽  
Vol 99 (1) ◽  
pp. 198-203
Author(s):  
Wu Bolong ◽  
Zhang Fengxia ◽  
Ma Xiaoning ◽  
Zhou Fengjuan ◽  
Sharon L Brunelle
Keyword(s):  
Infant Formula ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Method Performance ◽  
Performance Requirement ◽  
Whole Milk ◽  
Nist Standard Reference Material ◽  
Whole Milk Powder

Abstract A potentiometric method for determination of chloride was validated against AOAC Standard Method Performance Requirement (SMPR®) 2014.015. Ten AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1849a, were tested in duplicate on 6 independent days. The repeatability (RSDr) ranged from 0.43 to 1.34%, and the intermediate reproducibility (RSDiR) ranged from 0.80 to 3.04%. All results for NIST SRM 1849a were within the range of the certified concentration (701 ± 17 mg/100 g). Recovery was demonstrated with two overspike levels, 50 and 100%, in the 10 SPIFAN matrixes. Samples were tested in duplicate on 3 different days, and all results were within the SMPR requirement of 95 to 105%. The LOQs of the method for powdered products and ready-to-feed or reconstituted products were 20 mg/100 g and 2.2 mg/100 mL, respectively. A wide analytical range from the LOQ to 99.5% chlorine content can be reached with an appropriate dilution factor, but in practice, the upper analytical value observed in routine matrix testing was approximately 1080 mg/100 g in skim milk powder. This is a rapid, simple, and reliable chlorine-testing method applicable to infant formula, adult nutritionals, and ingredients used in these dairy-based products, such as skim milk powder, desalted whey powder, whey protein powder, and whole milk powder.

A laboratory study of continuous fermentation of skim-milk for the production of sour curd cheese

1971 ◽  
Vol 38 (2) ◽  
pp. 137-144 ◽  
Author(s):  
P. M. Linklater ◽  
C. J. Griffin
Keyword(s):  
Continuous Fermentation ◽  
Plug Flow ◽  
Milk Powder ◽  
Skim Milk ◽  
Fermented Milk ◽  
Skim Milk Powder ◽  
Fresh Milk ◽  
Batch Fermenter ◽  
Total Residence Time ◽  
Reconstituted Milk

SummaryThe feasibility of 2-stage continuous fermentation of skim-milk to produce sour curd cheese (quarg) has been established. The first stage was a stirred pH-stat fermenter, operated at pH 5·4, 5·6, 5·8 and 6·0, in which the operating pH was maintained by inflowing fresh milk. The remaining fermentation down to pH 4·7 was carried out by a procedure which simulated a second-stage plug flow fermenter (i.e. one in which forward velocity was as constant as possible at all points of the crosssection).Skim-milk powder was dissolved to give 8, 10, 14 and 20% solids in the reconstituted milk. Maximum productivity of fermented milk solids was obtained with reconstituted milk containing 20% solids and operation of the first-stage fermenter at pH 5·4. This 2-stage continuous fermentation gave a total residence time of about 5 h, which represents a rate of production 4·8 times that obtainable in 24 h in a batch fermenter of the same fluid capacity filled once daily with the same reconstituted milk.

Determination of Aflatoxin Mt in Milk by Liquid Chromatography with Fluorescence Detection

1984 ◽  
Vol 67 (1) ◽  
pp. 49-51
Author(s):  
Huguette Cohen ◽  
Michel Lapointe ◽  
Jean Marc Fremy
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Milk Powder ◽  
Skim Milk ◽  
Final Analysis ◽  
Skim Milk Powder ◽  
Radial Compression ◽  
Fluorescence Detector ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is proposed for the determination of aflatoxin Mi in milk. The method was successfully applied to both liquid whole and skim milk and also whole and skim milk powder. The samples are initially extracted with acetonitrile–water followed by purification using a silica gel cartridge and a C18 cartridge. Final analysis by LC was achieved using a radial compression module equipped with a 5 μm C18 column and a fluorescence detector. The method was successfully applied to samples at levels of 10 to 0.08 ppb added aflatoxin Mi with recoveries in the range of 70–98%.

Partial substitution of 40 g/100 g fresh milk with reconstituted low heat skim milk powder in high-moisture mozzarella cheese production: Rheological and water-related properties

LWT ◽  
2021 ◽  
Vol 137 ◽  
pp. 110391
Author(s):  
Flavio Tidona ◽  
Marcello Alinovi ◽  
Salvatore Francolino ◽  
Gianluca Brusa ◽  
Roberta Ghiglietti ◽  
...  
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Partial Substitution ◽  
Mozzarella Cheese ◽  
High Moisture ◽  
Fresh Milk ◽  
Cheese Production

QUALITY OF PROTEIN IN MILK REPLACERS FOR YOUNG CALVES. I. FACTORS AFFECTING IN VITRO CURD FORMATION BY RENNET (CHYMOSIN, RENNIN) FROM RECONSTITUTED SKIM MILK POWDER

1976 ◽  
Vol 56 (2) ◽  
pp. 317-325 ◽  
Author(s):  
D. B. EMMONS ◽  
E. E. LISTER
Keyword(s):  
Heat Treatment ◽  
Milk Powder ◽  
Skim Milk ◽  
High Heat ◽  
Skim Milk Powder ◽  
Factors Affecting ◽  
Fresh Milk ◽  
Milk Solids ◽  
Milk Replacers

Fresh milk coagulates with chymosin (rennin) in the calf stomach to form relatively strong curds. With respect to calf milk replacers it is of interest to study factors affecting curd formation of reconstituted skim milk powder by this enzyme. Curd firmness was increased by lower pH of the skim milk over a range of 5.6–6.6, higher concentration of skim milk solids over a range of 5–20%, higher concentrations of chymosin, lower temperatures of heat treatment of skim milk prior to spray drying, and higher temperature of coagulation, 37 vs. 30 C. Reconstitution of powder in water above 56 C for 2 min remarkedly reduced the firmness of the curd. The following coagulation conditions were selected for comparison of powders and milk replacers: addition of 1 ml of a 1:50 dilution of standard strength commercial rennet to 100 ml of milk previously adjusted to pH 6.1, 10% of nonfat solids in the aqueous nonfat phase, temperature of 37 C, and measurements of firmness 30 min after adding rennet. Commercially produced skim milk powders designated high-heat, medium-heat and roller products yielded soft curds. Commercial low-heat powders yielded strong curds. All coagulated in less than 4 min at pH 6.1, the time being relatively independent of heat treatment.

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