Edible Products. 



222 



THE CONSERVATION OF FRUIT BY THE USE OF FORMALIN. 



A good method of conserving fruit in as nearly as possible its "natural state 

 has been largely sought after for a long time, but Avhatever means have been 

 employed, a perfect result has not been obtained. One reason is tlie rapidity with 

 Avhich fleshy fruits ferment and rot under the action — as Pasteur has demonstrated 

 — of various organisms, fungus, and bacteria. Taking this view, and believing 

 that if these micro-organisms could be destroyed, the period during which the 

 fruit can be kept in perfect condition might be considerably prolonged, the English 

 agricultural authorities have instituted a series of experiments under the direction 

 of the Jodrell Laboratory, Kew. These have been very successful. The English 

 Journal of the Board of Agriculture reviewed them in a recent number (No. 5, 

 August, 1905, "Method of preventing the rapid decay of ripe fruit"). This high 

 authority gives its fullest support to the scheme. 



The method which has produced the best results is to immerse the fruit 

 in cold water containing 3 per cent, of trade solution of formalin (40 per cent, of 

 formaldehyde). 



There are two methods employed, according as the fruit has a soft pulp 

 or is firm-fleshed, and whether it is eaten whole or not. With the former class, 

 to which cherries, strawberries, grapes, &c, belong, the fruit is plunged into the 

 solution for ten minutes. Then it is taken out and steeped for five minutes longer 

 in cold water, and is finally spread out on a metal strainer, or in any other suitable 

 place, to allow it to drain and dry. In the second case, when the fruit has a peel 

 or skin which is not eaten, it is subjected to the formalin solution only. 



The Kew experiments were carried out on five kinds of fruit— cherries, 

 strawberries, gooseberries, pears, and grapes. These had not been specially 

 selected, but were bought in fruit-shops, and in some cases from street vendors. 



The following figures show the number of days during which the fruit 

 so treated remained perfectly souud, after an equal quantity of each fruit, non- 

 treated, taken for comparison, had become rotten :— Cherries, 7 days ; strawberries, 

 4; gooseberries, 7 ; pears, 10; and grapes 4 ; . These results apply in every case 

 to fruits which were perfectly ripe at the time of treatment ; but if they are 

 subjected to the process before maturity, they keep just as well, while the normal 

 development and flavour undergoes no more alteration than when the fruit is 

 placed in a refrigerator. It would have been interesting to know the length of 

 time which elapsed between the beginning and end of the experiment, in addition 

 to the number of days during which the treated fruit remained in good condition 

 longer than the other. The practical English people, having proved that this 

 method of conservation is excellent for their indigenous fruits, are hoping to 

 see their markets supplied with several delicious varieties of tropical fruits which, 

 under former conditions, has been impossible. 



A minute examination of ripe fruit from the West Indies intended for the 

 Colonial Produce Exhibition at the Crystal Palace, clearly showed that the 

 decomposition of the mangoes, for instance, during the journey was entirely owing 

 to mould and fermentation caused by bacteria and fungi attacking the outer 

 surface, and not owing to a tendency of the fruit to decay or ripen too quickly. 

 A similar treatment could be profitably employed on a number of tropical fruits 

 which are imported in a good condition (such as bananas), but which often have 

 a dark and disagreeable appearance, caused by an exterior fungus. Pears, apples, 

 oranges, citrons, &c, might all be treated with the same advantage. In England 

 great importance is attached to this new means of conservation, which is at once 

 very simple, inexpensive, and absolutely harmless. Several other preservatives 

 have been tried, but taking all conditions into consideration— ease of application, 



