326. The effect of temperature of pre-heating, of clarification and of bacteriological quality of the raw milk on the keeping properties of whole-milk powder dried by the Kestner Spray Process

1945 ◽  
Vol 14 (1-2) ◽  
pp. 116-159 ◽  
Author(s):  
A. T. K. Mattick ◽  
Edith R. Hiscox ◽  
E. L. Crossley ◽  
C. H. Lea ◽  
J. D. Findlay ◽  
...  

(1) Increasing the pre-heating temperature of the milk from 165 to 190° F. before spray-drying greatly improved the resistance of the powder to the development of tallowy ‘off’-flavours on storage. From the results of accelerated tests at 47 and 37° C. a storage life (in air) of the order of 2 years could safely be predicted for the powders from milk pre-heated at the higher temperature. Confirmation has now been obtained by storage of the powders for 2½ years at 15° C. and at room temperature.(2) Improvement in the bacteriological quality of the milk supply, and more careful control during its passage through the plant, produced some improvement in the keeping properties of powders prepared from milk pre-heated at the lower temperature, but had relatively little effect on the keeping properties of the powder when the higher preheating temperature was used.(3) The shapes of the deterioration curves for the various powders showed that the effect of the higher pre-heating temperature and of improvement in the milk supply was to extend the induction period which precedes rapid deterioration. The protective effect of both factors was greater when measured at the ‘slightly tallowy’ or ‘fairly good’ stage than when comparison was made at a more advanced stage of decomposition.

1945 ◽  
Vol 14 (1-2) ◽  
pp. 175-183 ◽  
Author(s):  
Edith R. Hiscox

Bacteriological standards are used in the assessment of the quality of dried milk powder. From a knowledge of total numbers of bacteria and the relative numbers of the various types deductions are made as to the quality of the raw milk supply, the cleanliness of the plant and the over-all efficiency of the process. Figures have been published by several workers showing plate counts of roller- and spray-dried milk powder, but the technique of reconstituting and of plating varied. Sterile water appears to have been the general reconstituting fluid, but sometimes lithium hydroxide (N/10 solution) was used, especially when the powder was difficult to dissolve. The temperature of the reconstituting fluid is not always mentioned, but it appears to have varied from room temperature to 60–65° C. The usual incubation temperature for the plates was 37° C, though 21–22 and 55–56° C. were also used for special purposes. InStandard Methods for the Examination of Dairy Products, eighth edition (1), the technique laid down mentions water, carefully warmed to 43–49° C, as the reconstituting fluid, and either 37 or 32° C. (for 48 hr.) as the incubation temperature, the choice being left to theenforcement officials having jurisdiction. American workers have for some years strongly advocated the use of 32 rather than 37° C. as the incubation temperature for routine plate counts of samples of raw milk, the advantage being that slight inaccuracies in the temperature of the incubator have less influence on the plate count which is, moreover, closer to that obtained by direct counts. The data offered in this paper show that the advantage of a similar incubation temperature (30° C. was used in these experiments) is equally obvious in the plating of dried milk powder.


2020 ◽  
Vol 4 (1) ◽  
pp. 18 ◽  
Author(s):  
Yanhong Mu ◽  
Enrico Simonetto ◽  
Marco Scagnolari ◽  
Andrea Ghiotti

Hot stamping by partition heating of Al–Si coated boron steel sheets is currently utilized to produce parts of the car body-in-white with tailored microstructural and mechanical characteristics. This paper investigates the evolution of the Al–Si coating and its tribological and wear performances in the case of direct heating at the process temperatures of 700 °C, 800 °C, and 900 °C, skipping the preliminary austenitization as it may happen in the case of tailored tempered parts production. A specifically designed pin-on-disk configuration was used to reproduce at a laboratory scale the process thermo-mechanical cycle. The results show the morphological and chemical variation of the Al–Si coating with heating temperature, as well as that the friction coefficient, decreases with increased temperature. Furthermore, the results proved that the adhesive wear is the main mechanism at the lower temperature, while abrasive wear plays the major role at the higher temperature.


1948 ◽  
Vol 15 (3) ◽  
pp. 277-279 ◽  
Author(s):  
Constance Higginbottom

The increased use of dried-milk products in human feeding during recent years stimulated investigations into and more rigid control of the bacteriological quality.Spray-dried milk powder from the same eight British plants has been examined for bacteriological quality at this Institute in several different years and the results show the marked improvements which have been made.


2019 ◽  
Vol 7 (3) ◽  
pp. 417
Author(s):  
Anak Agung Gede Rai Giri Natha ◽  
A.A.P. Agung Suryawan Wiranatha ◽  
Sri Mulyani

The aims of this study were: 1) to determine the effect of temperature and the addition of abrasive ingredients on the epidermis of cocoa beans to the characteristics of body scrub creams, and  2) to obtain temperature and the addition of abrasive ingredients to the epidermis of cocoa beans to produce the best characteristic body scrub cream, and 3)  how the quality of body scrub cream changes during storage. The experimental design used in this study was a factorial randomized block design, which consisted of 2 factors. The first factor was the heating temperature which consists of two levels, namely temperature of 65 °C and 75 °C. The second factor was the addition of abrasive materials which consists of three levels namely 3 percent, 6 percent and 9 percent. All treatments were grouped into 3 groups to obtain 18 experimental units. The data obtained were analyzed by variance and  the Duncan test. The best result of body scrub cream is the treatment of heating temperature 65°C and the addition of powder epidermis of cocoa beans 9 percent  with the characteristics of pH 5.53, viscosity of 36,627 cp, content of phenolic compounds 21.631 mg GAE/g, aroma 5.85 and passions 5.55. pH, viscosity and total phenolic compounds are stable up to 6 weeks of storage. Keywords : epidermis of cocoa beans, body scrub, characteristic, temperature, addition of abrasives


1952 ◽  
Vol 19 (1) ◽  
pp. 63-71 ◽  
Author(s):  
J. Babad ◽  
A. Shenhav-Hetman

The keeping quality of various mixtures, made up of raw milk and skim milk-powder in varying proportions, has been studied. It has been found that the keeping quality of unpasteurized samples containing milk powder was slightly better than that of raw milk. The keeping quality of the pasteurized mixtures was satisfactory during the time of storage for 40 hr. at 23 and 18° C. and for 60 hr. at 10° C.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jiezhen Hu ◽  
Xuequn Cheng ◽  
Xiaogang Li ◽  
Peichang Deng ◽  
Gui Wang

The reinforced concrete structures have to survive high temperature and carbonation at low latitude region. The research on the effect of temperature and the effect of carbonation are vital to the corrosion of the rebars in concrete structures. The coupled effect of temperature and carbonation on the corrosion of rebars was researched by using the open circuit potential (OCP), the electrochemical impedance spectroscopy (EIS), and the potentiodynamic polarization (PP) measurement in the simulated concrete pore solutions (SPSs). The high temperature environment is conducive to the formation of passivated surface of rebars in SPSs, but the dissolution velocity of passivated surface is higher. The rebars have the greater capacity of passivity at lower temperature. The corrosion rate of rebars at higher temperature is smaller in moderate pH value (10.6) SPSs. The rebars suffer from serious corrosion in the pH = 9.6 SPSs at 318 K temperature.


Author(s):  
A. Bousbia ◽  
S. Boudalia ◽  
Y. Gueroui ◽  
B. Belaize ◽  
S. Meguelati ◽  
...  

The main objective of this study is to assess nutritional and hygienic qualities of raw milk collected in situ in dairy cattle farms in the region of Guelma, Algeria. For this purpose, a total of 144 milk samples were collected and analyzed to determine their physicochemical characteristics and bacteriological quality. Results showed an acceptable nutritional quality, with a poor bacteriological quality. The average contamination was 11.69 x 105 CFU ml-1 for total flora, against 23.44 x 105 CFU ml-1 for total Coliforms and 7.34 x 104 CFU ml-1 for fecal Coliforms. In addition, 6% of total samples were positive for Clostridium. For the suspected pathogenic flora, Staphylococcus aureus has been detected in 9 samples; however, all milk samples were devoid of Salmonella. The poor quality of milk reflects the dismal conditions of production and the no-control of hygienic practices.


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