No. 2(l92l) REMARKS ON CANNING 121 



shelling is a lengthy operation, and without some means of preser- 

 vation, the canner may often have to restrict his purchases and 

 packing of this very desirable fish. 



186. Fortunately this is now possible, by adopting the use of 

 'semi-dried' prawns, which were introduced as a complete 

 novelty in cured fish several years age at the Government Fish- 

 curing Yard at Tanur and are now very greatly in demand as 

 ordinary cured goods. These are prawns prepared as mentioned 

 in paragraph 184. Immediately after shelling, the prawns are 

 salted in saturated brine (24° B.) for about 20 minutes, according to 

 size; being shelled they absorb salt readily. The brined prawns 

 are then placed on trays and scini-dried either in the open air or in 

 a drier. Drying is only partial and is stopped when the prawns 

 are so firm that fairly strong pressure between finger and thumb 

 is needed to make an impression on them. In this condition they 

 will keep perfectly good for many days according to climate, and 

 always for some days. If the prawns were perfectly fresh when 

 boiled — and no others should be used — and if properly cleaned, 

 brined, and dried, they will develop no odour save that natural to 

 fresh prawns. These semi-dried prawns may therefore be kept till 

 next day or later especially if in a cool place with free aeration ; 

 on the Nilgiris at 6,000 feet elevation they keep perfectly good for 

 several weeks. 



When required for use they are soaked in warm water till 

 sufficiently — not wholly — desalted, and are then canned as fresh 

 prawns ; cans of these prawns cannot, if the work has been 

 properly done, be distinguished from fresh prawns. Obviously 

 these prawns can also be utilized for prawn paste even when 

 several days have elapsed after curing. 



This method also enables a cannery to obtain prawns from 

 other curing yards, and thus greatly to extend its operations. It 

 can be extended so as to obtain other fish if properly light-cured 

 at the source of supply. 



If ice is available it will of course be utilized to keep light- 

 cured fish cool till needed. 



187. Shelling is a tedious operation and there is some loss 

 of edible material ; lOO lb. of prawns fresh from the sea produce 

 from 35 lb. when shelled and ready for canning, small prawns 

 losing more in shelling than large ones ; the heads and shells when 

 dried sell well as manure, containing 3 to 4 per cent of nitrogen. 



