摘要:

SUMMARYThe thermal destruction rates ofStreptococcus faecalis, ATCC 7080, were determined in a selected group of meat and fish precooked frozen products. Data on heat transfer through these products in a hot air household electric oven, were also obtained. Accordingly, the theoretical thermal treatments required to render such products commercially sterile were computed following the procedure of the General method of process calculation for canned foods with some modification. Inoculated product tests were also made to confirm the adequacy of the computed thermal treatments.It is concluded that the procedure adopted for establishing the thermal treatment was accurate and proved feasible for this type of product. Based on the thermal resistance of our test strain, the heat treatments recommended on the commercial packages seem to be adequate, provided the heating and cooling procedures are similar to those followed in the present experiments. In the case of one product out of the five tested, however, the minimum recommended heating period fell short of the computed thermal requirement for that product.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00031.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYApplication of the 2,4‐dinitrophenylhydrazine method of Roe and co‐workers to plant extracts, wherein ascorbic acid was present largely or completely in the form of DHA and DKA, resulted in abnormal data, in the sense that the value of AA + DHA+ DKA was significantlylowerthan that of DHA + DKA. Such a discrepancy, though not to the same degree, was observed also when the analyses were carried out on solutions of DHA. The loss is believed to take place during H2S treatment, there being a correlation between the extent of loss and the duration of H2S treatment, in the majority of the experime

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00032.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYSlices of beef were heated to 130°, 150° and 195° F, irradiated at 0.1 and 5.0 megarads and stored at 34° F. The effect of these variables on free amino nitrogen, total soluble nitrogen and TCA‐soluble nitrogen was determined at 15‐day intervals during the 60‐day storage period. Increases in heating temperature reduced the rate of release of TSN and TCA‐soluble fractions. Amino nitrogen was reduced only at highest temperature employed. Irradiation increased the rate of release of these fractions. The release of amino nitrogen began immediately upon storage of raw beef. Major amounts of TSN were not released until after 15 days storage and TCA‐soluble nitrogen not until after 45 days storage. This suggests successive fragmentation of the initially

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00033.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe effect of temperature, particularly storage temperature, is one of the most important factors in controlling microbial populations of frozen foods. Adequate temperature control of frozen foods should limit the growth of microorganisms and insure maintenance of original quality and wholesomeness. This investigation was undertaken to show that correct storage temperatures do inhibit the growth of bacteria which might be considered as the source of potential public health hazard, while certain saprophytic species are able to survive and grow well at the, same low temperatures. The cultures were all isolated from chicken pies.Bacterial counts were determined by plating techniques on Brain Heart Infusion (BHI) agar after various time intervals up to 30 days at ‐13°, 0°, 5°, 10°, 20° and 37° C, using both BHI broth and chicken gravy as media. Very similar results were obtained in the two media.Escherichia coliandStreptococcus faecalishad a minimum growth temperature between 5° and 10° C for active reproduction. A minimum growth temperature between 5° and 10° C was observed for the culture ofStaphylococcus aureus.Of two cultures representing variants ofPseudomonas fluorescens, one culture followed the growth‐temperature pattern shown by the previously mentioned organisms and failed to grow at or below 5° C. The otherP. fluorescensculture grew rapidly at 5° C. Ability to grow at low temperatures is a constitutive characteristic of the organism and is not common to all types of bacteria. At refrigerator temperatures, the growth of the psychrophilic saprophytic species tested completely outstripped the growth of several bacteria of public health significance. This indicates the great likelihood that a frozen food on defrosting, particularly in a refrigerator, would become completely unacceptable, due to the development of off flavors and odors and deteriorated physical appearance before it became

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00034.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYColor data on stored spinach and cauliflower were correlated with judges’scores to determine best sampling procedures for measurements with the Hunter Color and Color‐Difference Meter. Spinach stems, rather than leaves or mixtures, changed the most and most uniformly, correlated best with scores, and produced the smallest experimental errors. Cauliflower floret surface, instead of stems or mixture, gave smallest significant differences by judges. Good results on the instrument were obtained for both floret surface and a rapidly prepared slurry from a thin surface layer. Best of six color indices of deterioration were Hunter “a” and h

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYFrom four of the major islands in the Hawaiian chain, 19 foods of plant origin, the soil in which they were grown and the water used for irrigation were assayed for sodium. Data on the influence of environment upon the sodium content of fruits and vegetables are given. Most fruits and vegetables were low in sodium. A few, such as papaya, beets, celery, daikon, and sweetpotato, were high and probably should be omitted from very restricted sodium diets. The sodium concentration of some of the foods varied with the soil sodium concentration, which points out the necessity of considering the source of these particular foods before using them in a sodium‐restricted diet. The results indicate that variations in sodium should be expected in plant foods, although the differences may not always be nutritionally significan

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00036.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe many species of rockfish found in Pacific Coast waters represent an abundant source of seafood, which is available during all seasons of the year. The edible portion is processed as fillets either fresh or frozen. Composition of these fillets for the more important commercial species have been found to be high in protein and low in both oil and sodium. The values remain quite uniform for the different species regardless of the size of the fish, the season of its capture, or the manner in which it is stored and processed. The nonedible parts provide a valuable source of animal food since they are high in protein, oil, and ash. Thus the entire fish can be utilized in an economical manner.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00037.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe Girard‐T reagent was used to recover the aldehydes from cold‐pressed lemon, orange and grapefruit oils for subsequent quantitative gas chromatographic analysis. Optimum conditions for analysis were worked out with a known mixture of citral and the saturated aliphatic aldehydes which occur in major concentration in lemon oil. Isopropanol was used in the preparative step to eliminate acetal formation and isopentane in the final extractions to reduce losses of the lower‐molecular‐weight aldehydes during vacuum concentration of the sample for gas chromatographic analysis. Typical analyses are given for samples of domestic cold‐pressed ci

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00038.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe total carotenoid pigments of pineapple fruit contain a high proportion of epoxide groups which are readily isomerized to furanoid forms in an acid but not an alkaline environment. This isomerization causes a characteristic hypsochromic shift in the absorption maxima of the pigment extract. The absorbance at 425 mμ remains relatively unchanged as isomerization proceeds, and thus can serve as a measure of the total carotenoid pigment regardless of its isomeric form. The sharp maximum at 466 mμ is lost as isomerization progresses. Thus, the ratio of absorbances at 466 and 425 mμ can serve as a measure of the extent of isomerization of the pigmen

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00039.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe acid‐catalyzed isomerization of pineapple fruit carotenoid pigments is influenced by any condition leading to loss of integrity of the cells of the fruit tissue. The swollen lower half of fully ripe, yellow, translucent fruit often will contain an appreciable fraction of isomerized pigment. Any post‐harvest handling of the fruit that causes bruising of the tissue will lead to pigment isomerization in the damaged areas. Canning completely isomerizes the carotenoid pigments. Frozen fruit contains a high proportion of isomerized carotenoids; after thawing, further change takes place until the spectrum is that of the isomerized or “canned” type

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1961.tb00040.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY