摘要:

Spoilage, as measured by rise in trimethylamine and bacterial content, of cod press-juice containing 21.0 g. salt per 100 ml. (approximately 80 per cent saturated) is delayed longest with pure sodium chloride, and increasingly less with mined evaporated, mined crude, Mediterranean and Turk's Island solar salts. This order corresponds to decreasing percentages of sodium chloride and increasing percentages of impurities in these salts. The differences in the salt action increase with lower temperatures.

ISSN:0706-652X    

DOI:10.1139/f42-001

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Growth of 25 strains of red halophiles stopped below 15° and above 55°; heat resistance is less than two minutes at 98 °C. in 24 per cent saline. Range of relative humidity necessary for growth lies between 70 and 85 per cent. They have high resistance to ultra-violet light, surviving 120 minutes' exposure. Range of salt tolerance can be increased in both directions by gradual adaptation. Replacement of the Na ion by other cations inhibits growth.

ISSN:0706-652X    

DOI:10.1139/f42-002

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Fumigation with formaldehyde or sulphurous acid vapours was found effective against directly exposed red halophiles, using 10 oz. (283 g.) of the former or 5 lb. (2.268 kg.) sulphur per 1,000 cu. ft. (28.3 cu. m.) space. Formaldehyde solution 1:1,000 stopped growth in one minute, in absence of protein.Curing salt mixtures containing 2 per cent sodium acid phosphate and 0.25 per cent sodium benzoate stopped growth of red halophiles as well as brown halophilic dun molds. Dips in preservative solutions are not effective.

ISSN:0706-652X    

DOI:10.1139/f42-003

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Heavy infestations of this copepod in various developmental stages occur onSalmo salarandSalvelinus fontinalisat Moser River, N.S. Males and females occur in about equal numbers. Metanauplius and chalimus stages were present on the fins of the hosts. The male and four of the developmental stages are described and figures given. The parasite feeds on the skin of its host.

ISSN:0706-652X    

DOI:10.1139/f42-004

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Two agonid fish from British Columbia are regarded as aberrant, perhaps mutant examples ofOdontopyxis trispinosus. Their chief distinctive feature is the fusion, at some point before the dorsal fin, of the dorsal shields and keels, which are normally paired in this region. In this respect only, they approachBothragonus swanii. The variants show a tendency toward aberrancy in some other characters, but in most respects are typical ofOdontopyxis trispinosus.

ISSN:0706-652X    

DOI:10.1139/f42-005

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Atlantic salmon select as redd sites places where the current is accelerating. Eggs in the redd are in definite pockets associated with large gravel and stones, and are not scattered through the redd. The completed redd is figured. In Moser river, Nova Scotia, the spawning beds are poor and few. Eggs are smothered in some redds. Artificial spawning beds were prepared and were promptly used by the salmon. These provide a means of extending the area for successful natural spawning.

ISSN:0706-652X    

DOI:10.1139/f42-006

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

The products of fermentation of glucose by "resting cell" suspensions of certain bacteria (Serratia,Achromobacter, andMicrococcus) isolated from decomposing cod muscle include lactic acid, acetic acid, formic acid, ethyl alcohol, carbon dioxide and small amounts of acetylmethylcarbinol. With increased acidity in the fermentation system there is a marked increase in the percentage of lactic acid formed, with a corresponding decrease in the other products. The optimum pH for the fermentation of glucose appears to be in the vicinity of 6.8—that is at, or near, the pH of fresh cod muscle.

ISSN:0706-652X    

DOI:10.1139/f42-007

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

The contact plate method as used for cod muscle has revealed that the major changes rendering fish unfit for human consumption can be attributed almost entirely to surface pollution of the fish with spoilage bacteria. This is confirmed by three chemical tests, trimethylamine, tyrosine, and surface pH. The relative rates of increase in all three are much greater at the surface than in the interior of cod and haddock fillets. The more rapid surface changes are taken as evidence that tests for spoilage in fish products should be based on samples from the surface of the products and not from composite samples.

ISSN:0706-652X    

DOI:10.1139/f42-008

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Incorporation of sodium nitrite in the diet of cats and white rats on the basis of an average sized man consuming 1 lb. (454 g.) of fish containing 0.2 per cent (908 mg.) of this salt daily for six days each week does not appear to affect their growth rate nor the development (weight) of their thyroid, heart, lungs, spleen, liver, kidneys or adrenals. The fecundity of white rats as judged by their ability to breed and raise normal litters is apparently not affected thereby. The lethal dose of sodium nitrite by oral route is about 1.1 to 2.0 g./kg. for healthy male rats, 0.46 to 1.2 g./kg. for healthy female rats and 0.073 g./kg. for cats (one animal). The lethal dose by subcutaneous route is about 0.19 to 0.20 g./kg. for healthy male rats and 0.057 to 0.13 g./kg. for healthy female rats.

ISSN:0706-652X    

DOI:10.1139/f42-009

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Growth of the obligate anaerobesClostridium botulinumandC.sporogenesis inhibited by 0.02 per cent sodium nitrite in fish digest broth at acid pH, inhibition not being accentuated by brief exposure of the cultures to air during the vigorous growth phase. Sodium nitrite inhibits growth of facultative anaerobes in nutrient broth under both strictly and semi-anaerobic conditions. Growth of facultative anaerobes is inhibited by sodium nitrite over a much wider pH range in nutrient broth than in fish digest broth or in a simple synthetic ammonium lactate medium. Sodium nitrite is capable of acting in either bactericidal or bacteriostatic capacity under different conditions, and inhibits growth of the human pathogensEberthella typhosaandStaphylococcus aureus. The experiments described throw no light on the mechanism by which sodium nitrite, or its decomposition products, inhibit bacterial growth.

ISSN:0706-652X    

DOI:10.1139/f42-010

出版商:NRC Research Press    

年代:1942

数据来源: NRC