338. The ferric thiocyanate method of estimating peroxide in the fat of butter, milk and dried milk

1946 ◽  
Vol 14 (3) ◽  
pp. 340-353 ◽  
Author(s):  
G. Loftus Hills ◽  
C. C. Thiel
Keyword(s):  
Aqueous Solution ◽  
Peroxide Value ◽  
Milk Powder ◽  
Ferric Thiocyanate ◽  
Ferrous Salt ◽  
Modified Method ◽  
Whole Milk ◽  
Butter Milk ◽  
Whole Milk Powder

The ferric thiocyanate method of estimating peroxide in fats has been modified to give greater sensitivity and greater stability of the reagent. As the 96% acetone used by Chapman & McFarlane (3)and Lips et al.(4) only dissolves about 0.5% butterfat, the sensitivity of the test was increased by using, as solvent, the mixture of benzene and methanol used by Bolland et al. (6) in the determination of rubber peroxides, which dissolves at least 10% butterfat. Instead of using a prepared reagent which gradually deteriorates, the ferrous salt and thiocyanate are added in aqueous solution during the test, and, moreover, ferrous salts appear to be more stable in this solvent than in acetone. The modified method is sufficiently sensitive to measure the peroxide value of the fat of freshly drawn milk and has been applied to the study of the first stages of oxidation in milk, butter and whole-milk powder.

scholarly journals Salmonella Detection in Dried Milk Products by Motility Enrichment on Modified Semisolid Rappaport-Vassiliadis Medium: Collaborative Study

1996 ◽  
Vol 79 (2) ◽  
pp. 441-450 ◽  
Author(s):  
Robert F Bolderduk ◽  
John E Milas ◽  
H Asperger ◽  
H Becker ◽  
S Chatron ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Milk Powder ◽  
Culture Method ◽  
Milk Products ◽  
Whey Powder ◽  
Whole Milk ◽  
Significant Difference ◽  
Powder Samples ◽  
Butter Milk ◽  
Whole Milk Powder

Abstract A collaborative study involving 19 laboratories was performed to validate motility enrichment on modified semisolid Rappaport-Vassiliadis (MSRV) medium for rapid detection of motile Salmonella in dried milk products. The MSRV method was compared with the AOAC culture method for detection of Salmonella in nonfat milk powder, whole milk powder, whey powder, casein powder, and butter milk powder. Samples were artificially inoculated with Salmonella at 2 levels of contamination. Un-inoculated control samples were included for each type of product. The sensitivity rates were 100% for the MSRV method and 99.0% for the AOAC culture method, while the specificity rate was 100.0% for both methods. Only for the samples of whey powder, which were inoculated with H2S negative S. tennessee, was there a significant difference in the proportion of samples positive by MSRV and the culture procedure. The MSRV method for detection of motileSalmonella in dried milk products has been adopted first action by AOAC INTERNATIONAL.

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.

341. The effect of the pre-heating temperature on the bacterial count and storage life of whole milk powder spray-dried by the Krause process

1946 ◽  
Vol 14 (3) ◽  
pp. 378-399 ◽  
Author(s):  
J. D. Findlay ◽  
Constance Higginbottom ◽  
J. A. B. Smith
Keyword(s):  
Room Temperature ◽  
Heating Temperature ◽  
Milk Powder ◽  
Bacterial Count ◽  
Strong Reaction ◽  
Whole Milk ◽  
Whole Milk Powder ◽  
And Storage ◽  
Spray Dried

1. Storage tests on spray-dried full-cream milk powders prepared from milk preheated at 160,170,180, 190 and 200° F. for approximately 20 sec. and dried by the Krause process have been carried out at 47, 37 and 15° C. or room temperature. The storage tests were carried out independently at two different research stations. At the Hannah Institute the powders were packed in plain tin-plate containers as received from the factory. At Cambridge grease-free plain tin-plate and lacquered tin-plate containers were used. Deterioration was followed at both stations by a tasting panel and by determination of the amount of oxygen absorbed by the powder and of the accumulation of peroxide in the fat.2. When fresh the powder pre-heated at 180° F. had the best flavour, followed in order of preference by those pre-heated at 190 and 200° F., which had a definite but quite pleasant ‘boiled’ or ‘cooked’ flavour, and by those pre-heated at 160 and 170° F. which had an incipient tallowy flavour, but were nevertheless still acceptable. The 200 and 190° F. powders gave a strong reaction for volatile sulphur, the 180° F. powder a much weaker but quite definite reaction, and the 170 and 160° F. powders a negative reaction. The copper content of the 180° F. powder which, with the 170° F. sample, was the highest of the group, may have been partly responsible for the weakness of the reaction for volatile sulphur given by this sample. The solubility of the 180, 190 and 200° F. powders was not adversely affected by the high pre-heating temperatures, and the moisture contents of all the powders were sufficiently low to prevent any obvious loss of solubility, which remained very good indeed throughout the storage tests.

The effect of antioxidants on the keeping quality of whole milk powder: II. Tocopherols

1965 ◽  
Vol 32 (2) ◽  
pp. 143-146 ◽  
Author(s):  
J. Abbot ◽  
R. Waite
Keyword(s):  
Peroxide Value ◽  
Milk Powder ◽  
Dodecyl Gallate ◽  
Whole Milk ◽  
Keeping Quality ◽  
Whole Milk Powder ◽  
Spray Dried

SummarySpray-dried whole milk powders were prepared containing 0·01% of γ-tocopherol and of a mixture of α-γ- and δ-tocopherols. Control powders and powders containing 0·01% of dodecyl gallate, an antioxidant of known effectiveness, were also made. The powders were stored at 37°C and examined at intervals for taste, peroxide value and absorbed oxygen. The protection against oxidation afforded by both the tocopherol additions was small, although γ-tocopherol was more effective than the mixture of tocopherols. Dodecyl gallate was again found to be a good antioxidant for whole milk powder.

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