Edible Products 



[April, 1909. 



"kiln drying" lias been devised; in 

 this heated air is passed through the 

 maize until the superfluous moisture is 

 removed. It is stated by some that 

 the heat injures the maize for manu- 

 facturing purposes, and that the kiln- 

 dried maize is liable to suffer consider- 

 able damage by cracking and breaking 

 during subsequent handling operations; 

 the objection to kiln drying, however, 

 may partly have arisen from badly 

 damaged material having sometimes 

 been treated and mixed with better 

 grades. There seems no reason why, 

 either by using a lower temperature for 

 the air and prolonging the time of dry- 

 ing, or by using air previously deprived 

 of its moisture by refrigeration, and 

 then warmed, some suitable method of 

 drying maize should not be attained. 



An alternative plan to storing in a 

 ventilated crib is to allow the maize 

 to dry thoroughly before storing, and 

 then to keep it in a tightly closed bin 

 in which it can be treated to destroy 

 insects ; in some climates the slow dry- 

 ing in the ventilated crib would not 

 be successful. 



Having regard to the injury caused 

 by dampness it is important that the 

 grain should not be exposed to rain 

 in the course of transport by land, 

 warehousing and shipping, nor to damp 

 air during the voyage; and the stores 

 should be dry and thoroughly well 

 ventilated, and be kept clean and white- 

 washed. 



Among the insect enemies of maize 

 weevils cause an immense amount of 

 damage, especially to that coming from 

 West Africa; it seems probable that 

 the chief source of infection is the 

 warehouse where the maize is collect- 

 ed before shipment, though the attack 

 may commence at the country farms, 

 and some of these insects may be 

 lurking in the holds of the steamers 

 that convey the maize to England. 

 The larva? of some moths also attack 

 the grain. 



Weevils and moths can be easily 

 killed by the use of carbon bisulphide, 

 a colourless volatile liquid which gives 

 off a heavy vapour, but its use in 

 tropical countries will require careful 

 supervision owing to its poisonous 

 properties and great inflammability. It 

 may be applied either by spraying or 

 pouring the liquid over the gram, but 

 it is commonly put in shallow pans 

 placed above the grain ; from these it 

 evaporates, and the heavy vapour sink- 

 ing through the grain kills the insects. 

 The best results are obtained when the 

 grain is stored in air-tight bins or 

 closed tanks ; but in absence of these, 

 covering the grain with tarpaulins, oil 



cloths, or canvas sails will be tound 

 effective. It is a good plan to build 

 a " quarantine bin, " in which the 

 grain is treated and afterwards removed 

 to the store. The carbon bisulphide 

 is used at the rate of 1 lb. to each 100 

 bushels of grain, and is allowed to act 

 for from 24 to 48 hours. 



Buildings can sometimes be treated 

 with this substance, using 1 lb. of the 

 liquid for 1,000 cubic feet of space, and 

 placing it high up so that the vapour 

 may descend ; apertures should be 

 closed and the building kept shut for 

 from 5 to 12 hours. When opened the 

 building should be well ventilated. 

 Every pracaution must be taken to 

 prevent the vapour igniting by con- 

 tact with lights or pipes, or even the 

 sparks from electric fittings, as its 

 igniting temperature is very low, and 

 when mixed with air it is explosive. 

 The vapour is poisonous, and must not 

 be breathed, and workmen in factories 

 where it is used are found to suffer 

 from constantly inhaling small quanti- 

 ties. It should not be used for flour, but 

 grain is uninjured by the treatment if 

 it is well ventilated afterwards, 



As an alternative to using carbon 

 bisulphide to destroy the insects the 

 plan of heating might be employed. It 

 has been found by Mr. F. V. Theobald, 

 in the case of other grain, that any dry 

 temperature over 140° F. killed all larvae 

 and pupa? as soon as the corn was well 

 warmed through ; the most successful 

 experiments were at any temperature 

 between 130° to 140° F., when not only 

 larva? and pupte but also eggs and adults 

 were killed, and it seems probable that 

 on the large scale heatine: to a temper- 

 ature approaching 150° F. for one hour 

 would be successful. The designing of 

 an apparatus to effect the destruction 

 of weevils by heat without at the same 

 time injuring the commercial value of 

 the maize deserves the attention of 

 manufacturers of milling machinery. 

 The treatment should be given at the 

 warehouse before shipping, and as soon 

 as possible after the maize is received; 

 the maize should then be stored away 

 from danger of fresh infection until 

 shipped. Messrs. Thomas ;Robinson & 

 Son, Limited, of Rochdale, England, 

 make a maize-drying machine which 

 might, perhaps, prove effective for 

 this purpose; it is capable of dealing 

 with 150 bushels at a time. In this ap- 

 paratus air heated by steam coils is 

 blown by a fan through the maize 

 placed in specially constructed cham- 

 bers. 



Before shipping the holds should be 

 thoroughly cleaned and freed from 

 insects. It has been noticed by Mr. F. 



