Chapter XVI 



— 189 — 



Sanitary Aspects 



gators agree that the numbers and kinds of bacteria in the intestinal tract 

 of fish are dependent primarily upon the food ingested recently. Accord- 

 ing to Hunter (1920), Griffiths (1937), and others, the stomach and 

 intestine of fasting fish are frequently bacteria-free. 



The flora, which Wood (1940) isolated from salmon, barracouta, whit- 

 ing, mullet, and flathead taken from Australian waters, has a great deal in 

 common with that isolated from marine fish in other parts of the world 

 (see Table XL). He found that, if properly handled, fish may be kept 

 for as long as 8 days at 7° to 8° C. without becoming too stale to be edible. 

 After finding virtually no coliform bacteria of fecal origin. Wood con- 

 cluded that there should be little danger of epidemics due to the consump- 

 tion of fish, provided that a wide berth is given to sewer outfalls by fish- 

 ermen. 



Table XL. — The bacterial flora associated with fish and water, expressed as a percentage of 

 the cultures examined (from Wood, ip4o): — 



From salmon of North Pacific waters, Snow and Beard (1939) iso- 

 lated 1838 cultures which they identified as follows: 



The last four were found only in Columbia River salmon. Additional in- 

 formation on the kinds of bacteria associated with marine fish is given on 

 page 172. 



The controversial question of the bacterial content of fish flesh is re- 

 viewed by Griffiths (1937). It is generally agreed that the muscles of 

 healthy fish are usually sterile, although some investigators have experi- 

 enced difliculty in consistently obtaining sterile fish tissue. Infection of 

 the muscle occurs immediately after death, and the bacterial population 

 increases rapidly at a rate which is influenced primarily by the temper- 

 ature. Hunter (1920) observed an increase in the flesh of salmon from 

 zero at the time of catching to as high as 155,000,000 per gram after 96 

 hours' storage at from 10° to 21° C. During this period of storage the 

 salmon may be so decomposed as to become unfit for human consumption. 



KiSER and Beckwith (1944) found from none to 30,000 bacteria per 

 gram of muscle tissue of freshly caught mackerel and from none to 

 64,000,000 per gram of intestinal contents. Predominating were species 

 of Micrococcus, Achromohacler, Pseudotnotias, Flavohacterium, Sarcina, 

 Kurthia, Lactobacillus, and Streptococcus in the order named. 



