Fat test

Fresh raw milk that complies with sanitary standards for consumption as fluid milk or cream is usually clarified, standardized to a certain fat test, or separated into cream and skim milk. 

Table or coffee creams are those of intermediate fat content. In the United States they are classified as light (18% fat) and medium (30% fat), whereas in the United Kingdom they are designated cream (20% fat) and sterilized cream (23% fat). Other than sterilized creams, the table creams are standardized to the desired fat test, pasteurized, and packaged. To extend their shelf life, sterilized creams, as well as some table creams that are ultrapasteurized, are aseptically packaged. 

Interest in milk density is twofold. It has been used, along with the fat test, to estimate total solids contents. Raw milk is purchased by weight, but processed milk is sold by volume. 

Dill, C. W., Herlick, S. A., Richter, R. L., and Davis, J. W. 1979. Fat test depression during chilled storage of milk samples in plastic containers for analysis by the Milko-Tester J. Food Protection 42, 314-316. 

Golding, N. S. 1959. A solids-not-fat test for milk using density plastic beads as hydrometers. J. Dairy Sci. 42, 899. 

Melt the trans fat test samples in a water bath if necessary. Using a disposable pipet, place each on the ATR horizontal surface making sure that the surface of the ZnSe or diamond crytal is completely covered, collect a 128-scan single-beam FTIR spectrum (Fig. D1.7.1B) at 4 cm-1 resolution, and save it. Repeat step 5 after each measurement. 

Figure D1.7.1 (A) Absorption spectra for neat (without solvent) trans fat (test samples). (B)...

Electronically generate the absorbance spectra (Fig. D1.7.1 A) for all the calibration standards and the trans fat test samples by ratioing each of the saved single-beam spectra against that of the trans-free reference fat. 

For each of the calibration standards and the trans fat test samples, display the absorbance spectrum in the expanded wavenumber range of 1050 to 900 cm 1, and electronically integrate the area under the 966 cm"1 band between the 990 and 945 cm"1 limits. 

Figure D1.7.2 (A) Absorption spectra for carbon disulfide (CS2) solutions of trans fat (test...

As a result, the depth of penetration, or effective pathlength, will be higher the greater X or the smaller the frequency. Therefore, an interferogram (raw infrared spectrum) is a measure of the attenuation of a trans fat test sample of the totally internally reflected infrared light. The interferogram of a reference background material (trans-free fat) is similarly measured. These are subsequently used to obtain an absorption spectrum. 

It is essential to ensure that the test portion of the fat being analyzed completely covers the horizontal surface of the ATR crystal for the quantitative determination to succeed. In some cases, after placing a fat test portion on the ATR crystal, the melted or liquid fat beads up and partially rolls off the surface of the ATR crystal. The only recourse the analyst would have is to try again. 

Exposure to chlorobenzene can be determined by measuring the chemical or its metabolite in urine, exhaled air, blood, and body fat. Tests are not routinely available at the doctor s office. Specific tests are available that can determine if exposure is currently occurring or has occurred very recently, but not whether exposure occurred in the past. Further, levels in the various media stated above do not predict adverse health effects. Additional information on how chlorobenzene can be measured in exposed humans is given in Chapters 2 and 6. 

R17, Rose, H. G., and Juliano, J., Regulation of plasma lecithimcholesterol acyltransferase in man. III. Role of high density lipoprotein cholesteryl esters in the activating effect of a high-fat test meal. J. Lipid Res. 20, 399-407 (1979). 

Moreover, the first amendment to it, Council Directive 93/8/EEC, made the standard conditions for migration tests more flexible by allowing a greater number of possible combinations of times and temperatures and the use of other simulants for the fat test in cases where it is not possible to use those previously provided for. Table 12-9 shows the conditions which now apply. 

A second amendment, Directive 97/48/EEC, laid down the conditions of use of volatile solvents, e g. isooctane and ethanol, as test liquids in the fat test . It provided that these solvents may replace olive oil or the other fat simulants (HB 307, sunflower oil, etc.) if the fat test is not applicable in its basic version for technical reasons or in routine checking. These conditions are shown in Tables 12-10 and 12-11. 

All samples of human fat tested and reported in the United States show storage of DDT and its metabolite DDE (see Table I). Residue from food, particularly meat (5), is considered the most likely source... 

Problems of poor recovery during sample collection (requires use of markers), inadequate dietary fat (minimum of 70 g/day), inaccurate analysis and uncertain interpretation Butter fat test... 

Fatty acids (in milk fat) to a total of up to 10 mg were treated with 250 1 of di-n-butyl carbonate and 0.5 ml of 0.2 M sodium butoxide. The tube was capped and the mixture was heated for 2 minutes on a steam bath. The contents of the tube were transferred to a Babcock milk fat test bottle and rinsed in with 0.5 ml of water, 0.5 ml of acetone and a further 0.5 ml of water. Saturated NaCl (10 ml) was added and the volume was adjusted to the mark with water. The layers were separated by centrifugation and the upper layer was taken directly for analysis by gas chromatography [142]. 

The simple analysis of variance (Table XI) indicates that large differences in flavor were evident among the five fats tested as well as large differences in the judges scores within fats. These facts are evident from a consideration of the large F values, both of which are highly significant at P = 0.01. 

For very large and expensive projects it is worthwhile to include FAT. If possible staff from the pharmacy should participate in FAT tests in order to become familiar with the equipment and in order to detect failures as soon as possible - this can save a lot of time and money. 

A fat test is needed in order to establish the market value of milk and cream. Also, a fat test is important for numerous other purposes. For example, in Cheddar cheese 50% of the dry matter must be fat hence, a fat test provides a means of standardizing milk for the production of such cheese. Similarly, fat content must be known for the production of nonfat dry milk from skim milk, butter from cream, ice cream from numerous possible sources of fat, and evaporated milk from milk. 

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