摘要:

Investigations concerning the stability of a group of factors contained in cod liver residue and displaying vitamin B12activity have led to the conclusion that under the conditions prevailing during the rendering process, as developed at the Atlantic Fisheries Experimental Station, little or no deactivation occurs. This is in sharp contrast with what occurs under more drastic conditions such as used in the alkali-digestion process.The study of the microbiological method used for the determination of vitamin B12activity has shown that one step of the analytical procedure, namely, that phase during which the extraction of the sample is performed, is responsible for anomalous results. Deactivation occurs during this stage to an extent which varies according to the previous history of the material. The addition of thioglycolic acid or ascorbic acid during this period does not effectively protect the material unless culture medium is added as well. Medium alone is inefficient. Sodium bisulphite on the other hand exerts protection even in the absence of medium. This effect of sodium bisulphite applies not only to cod liver residue, but also to materials of diverse origin, mammalian viscera included. The data obtained show that vitamin B12itself is not involved; presumably vitamin B12aand vitamin B12bare, although there is no direct evidence of their presence in cod liver.As a protection during extraction, 0.08 per cent to 0.1 per cent of sodium bisulphite calculated on the amount of wet material appeared to be optimum.

ISSN:0706-652X    

DOI:10.1139/f52-006

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f52-007

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f52-008

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Two hundred and forty-five cultures ofFlavobacteriumwere isolated from fish; 16 per cent reduced trimethylamine oxide; 25 per cent reduced sodium nitrate; 50 per cent were proteolytic; 70 per cent grew at 2 °C. None fermented dextrose or hydrolysed fat.Many of the cultures produced a yellow discoloration but no offensive spoilage odours on fish muscle. Other strongly proteolytic cultures produced putrid odours at 5 to 8 days on fish stored at 3 °C.Under commercial conditions they are not as important in the development of spoilage as the more active achromogenic rods which rapidly outgrow theFlavobacteriumon stored fish.

ISSN:0706-652X    

DOI:10.1139/f52-009

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The relatively slow development of red halophilic bacteria on laboratory culture media has long been noticed to cause distinct disadvantages in the cultural studies of the types responsible for the reddening of salt fish. Thus, routine analyses of salt and salt fish samples for the presence of red bacteria and also disinfectant studies leading to the elimination of the resulting contamination are seriously delayed. Lochhead's skim milk-salt agar medium has been modified by the addition of MgSO4∙7H2O, 5 g.; Mg(NO3)2∙6H2O, 1 g.; FeCl3∙7H2O, 0.025 g.; Proteose Peptone No. 3, 5 g.; and glycerol C.P., 10 g. to 1000 ml. of medium. In addition/to technical improvements, definite stimulation of growth has been obtained; the incubation time being cut in half and the volume of growth several times incr

ISSN:0706-652X    

DOI:10.1139/f52-010

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Quantitative estimation of the amounts of vitamin B12-active substances in some marine invertebrates was made using a microbiological assay technique. In general, species from phylum Mollusca were found to be richer in these substances than were species from phyla Echinodermata and Annelida and class Crustacea. No definite relationship was found to exist between the content of vitamin B12-active substances in an animal and its phylogeny.

ISSN:0706-652X    

DOI:10.1139/f52-011

出版商:NRC Research Press    

年代:1952

数据来源: NRC