摘要:

SUMMARYSurvival curves were obtained for massive concentrations of spores of Clostridium botulinum strain 12885A, when subjected to a wide range of gamma radiation doses under various conditions. The spore concentrations ranged from 37,000 to 64,800,000,000 per ampoule, with no recovery at 5 Mrad or more. Only at lower doses were observed survival counts compatible with classical hit theory. More than one hit is apparently required to inactivate the Cl. botulinurn spore by gamma radiation. The number of hits required for inactivation is estimated at somewhere near 13. Freeze‐dried spores exhibited less radioresistance in the dry state than when resuspended in neutral phosphate buffer. Spore suspensions in neutral phosphate buffer exhibited less radioresistance when irradiated under air than when irradiated under nitrogen. Spores exhibited less radioresistance suspended in phosphate buffer than in a nutrient medium (pork‐pea infusion). Changes in concentration of spores over a range of 37 × 103to 53 × 109did not significantly affect the percent survival for a given dose except in the tail area. Regardless of spore concentration, a so‐called “tailing off” of surviving spores was observed at the higher dose levels employed for varying spore concentrations. The “tailing off” phenomenon did not appear to follow the class

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00101.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYAntibiotic activity in aged Liederkranz cheese was found to be produced by the aerobic microorganisms inhabiting its surface. Brevibacterium linens was the principal source of the antimicrobial agent(s). Yeast of the Candida type and, when present, some other microorganisms contributed minor antimicrobial activity. The antimicrobial agent(s) of aged Liederkranz cheese had the following properties: 1) dialysable through cellulose casing, 2) absorbed on Norit A at acid pH, 3) stable in acid and alkaline solutions ranging from pH 2.0 to 12.0 at 24° C, 4) destroyed within 20 hr in alkaline solution at pH 12 at room temperature, 5) in aqueous solution stable to heating at 121° C for 10 min at acid pH(pH<5.0) but decreased activity at pH 5.0 to 8.5, 6) in agar medium of pH 6.8–7.0 activity remained after heating at 121° C for 45 min, 7) soluble in water, methanol, ethanol, and butanol, slightly soluble in acetone and insoluble in ethyl ether, carbon tetrachloride, chloroform and ethyl acetate, 8) inhibited growth of many gram‐positive and gram‐negative bacteria as well as several yeasts and molds, and 9) related to antibiotic from B. linens but distinct from nisin, an antibiotic commonly associated with dairy products. In a survey of market samples of cheeses to determine whether antibiotic activity was present, only surface‐ripened cheeses with a brown smear made up of bacteria were found to contain antibacterial activity. Other types of cheeses which did not develop this brown smear did not possess this activity. It may be concluded that antibiotic activity is contained in the brown bacterial surface smear that develops durin

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00102.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYFrozen meat‐water extracts stored under lights exhibit a pattern of metmyoglobin formation similar to that in frozen steaks. The spectrophotometric method of analysis was satisfactory for estimating the percent metmyoglobin in the solutions. Fluorescent lights significantly increased the formation of metmyoglobin in the solutions, similar to that reported for frozen steaks. Dialyzing the extract inhibited the increase of metmyoglobin in the frozen solution when stored under light. Addition of copper, manganese, or calcium ions in the form of the chloride salts to the dialyzed solution did not increase rate of metmyoglobin formation appreciably. The addition of chloride salts of magnesium and iron contributed to an increase in the rate of metmyoglobin formation. When the dialysate was concentrated and added to the dialyzed residue there was a significant increase in the rate of metmyoglobin formatio

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00103.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe sodium 2,6‐dichlorohenzenoneindophenol method (Method A) and the diazotized 4‐methoxy‐2‐nitroaniline method (Method B) for measuring reduced ascorbic acid in frozen peas were compared. A randomized incomplete block design with 12 replications for each of the two methods of ascorbic acid analysis was used. Very highly significant differences in ascorbic acid values were obtained between Methods A and B, with Method A always the

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe rate of browning of 20 sugars or sugar derivatives was followed by reflectance measurements of cookies and spectrophotometric measurements of browning of dilute buffered solutions of the sugars and glycine or lysine, heated at 114°C in an autoclave. Both in cookies and in solution, the order of decreasing reactivity for the pentoses was: ribose, xylose, and arabinose. Among the hexoses, galactose was the most reactive and rhamnose the least. Because the conditions of pH and presence of amino acids were varied, no over‐all order of reactivity could be established for the other hexoses. Disaccharides with reducing groups, except melibiose, showed little reactivity. Sugars without reducing groups failed to exhibit browni

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYSixteen compounds in the volatile fraction of apple wine were isolated and identified. Ethyl chloride was preferred over pentane or iso‐pentane in extraction of the volatiles because it gave higher yields and its lower boiling point allowed almost solvent‐free extracts in a very short time. Gas‐liquid chromatography was used in separation and purification of the volatiles. The compounds were identified by comparing retention times, infrared spectra, and melting point of derivatives with those of known comp

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYSmall concentrations of linoleic and linolenic acids reduced the solubility of cod actomyosin rapidly. The extent of insolubilization depended on the structure of the fatty acid, on its concentration, and on the duration of storage of the fatty‐acid‐treated actomyosin solutions. The results support the hypothesis that the accumulation of free fatty acids in frozen fish muscle causes the actomyosin of the muscle to become inextracta

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYMethionine content of 24 of the more common foodstuffs used in South India is reported. Two independent methods were used, one based on the McCarthy and Sullivan color reaction and the other on filter‐paper disc chromatograph

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYA simple, direct calorimetric method requiring no distillation is described for the determination of potassium sorbate in dried fruits. The method makes use of the oxidation of sorbic acid to malonaldehyde, which reacts with thiobarbituric acid to form a red pigment that is measured photometrically.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe data from analyses of six potato varieties grown at nine widely different locations over two years showed that varietal comparisons for ascorbic acid content are relatively unaffected by location. Thus, in ascertaining the potential value of potato varieties as a source of ascorbic acid, widespread testing appears to offer no advantage over the determination of varietal differences for this factor in a more confined area.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1962.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY