CANNED SARDINES 105 



ounces; and the temperatures discussed are such as are applied to cans of this size. 

 The object of the heating is of course to sterilize the sardines, prevent subsequent 

 Spoiling and insure the necessary keeping qualities. In the majority of the factories 

 visited, the cans are immei'sed in baths of boiling water for a period of one and 

 hali to two hours; and where this method is adopted, no further heating is done; the 

 preparation of the sard'nes is presumed to be complete, and the product ready for 

 sale. In a few factories, the heating is done in retorts or autoelavs at a temperature 

 of 225°r. for a shorter period. This variation in treatment is sufficient reason for the 

 using of the term " heating " with verj- definite qualifications. To say that the sardines 

 are sterilized, when the heating has consisted of a treatment in boiling water even 

 for two hours, is not correct. Sterilization in the true sense of the term means heating 

 for such time, and to such temperature, as will kill all bacterial life. And the work 

 of Pasteur, in the early days of the study of bacteriology, proved conclusively that 

 wine for instance would always be subject to spoiling unless all bacterial life had been 

 destroyed. The same principle holds good in the case of sardines. It is important 

 that the possible sources of contamination shall be reduced to a minimum. Then, 

 if the cans have been proi>erly scaled, and in such manner as prevents the access of air 

 and consequently the bacteria which are present in the air, the presence or absence 

 of bacteria in the finished sardine product depends upon the efficiency or non-efficiency 

 of the heating. That such a large proportion of canned sardines heated in the manner 

 indicated are suitable for consumption is proof that the heating in the factories is 

 frequently satisfactory; but entire satisfaction is impossible unless all the cans are 

 fit for food. 



Those canners who use retorts or autoelavs are using a method, which, provided 

 the temperature is sufficiently high, and the heat assured for a proper length of time, 

 will efficiently sterilize the sardines. It will be possible to discuss the question of 

 heating, in the reixtrt on the later part of the investigation. For the present, it will 

 suffice to say that the heating must be sufficiently satisfactory to warrant the packer 

 in feeling justified when ho guarantees the quality of his product. 



Material examined. 



Some forty samples were examined. Swelled canned sardines were secured first- 

 hand from many of the canneries, from a city health department in the Maxntime 

 Provinces and from various retail grocery stores. A number of apparently normal 

 cans were also obtained from several sources. Owing to the varieties of " brands " of 

 sardines produced by the canning factories, the various methods of treatment, and 

 the different substances utilized for the giving of flavour and consistency to the 

 finished prodYict, it is not possible other than in a general way to describe the condi- 

 tions met with on the opening of the cans. 



APPEARANCE OF CANS. 



Normal C'a7i-s:. — In outward appearance there is a complete absence of any 

 "bulging"; the top and bottom are quite flat or almost imperceptibly concave; on 

 opening, the contents are found to be firm, not macerated and often white in colour; 

 this latter, however, depending to some extent lapon the materials used in the prepara- 

 tions for packing. The smell is mildly characteristic of the fish, qualified by the variety 

 of oil or tomato sauc« used. There is in appearance and odour, a complete absence of 

 putrefaction. 



Swelled Cans. — Outwardly the cans vary, from a slight "bulged" appearance to a 

 more pronounced swelling. The top and bottom are forced out as a result of the 

 pressure, and present a decided convex surface. As the swelling becomes greater, the 

 oil or sauce will be forced out between the soldered parts of the can, and in pronounced 

 cases the outside surface is greasy and wet, and possibly covered with the oil or sauce. 



