BROWNHEART.

Auckland Star, Volume LVI, Issue 162, 11 July 1925, Page 11

BROWNHEART.

FUNCTIONAL DISEASE IN APPLES. TOO MUCH CARBON DIOXIDE. IMPORTAXT INVESTIGATIONS. Cabled news has come to hand to the effect that Mr. Justice Branson, of ,the King's Bench Division, is taking evidence j in an important test action upon which other claims depend, relating to brownheart in apples. Messrs. Bradley and, Sons, Ltd., of Covent Garden, are claiming £4314 from the Federal Steam Navi- ( gation Company, owners of the steamer Northumberland, owing, to the development of brownheart in apples shipped by that vessel from Hobart in 1021. Plaintiffs allege that the disease in tlie fruit was due to bad ventilation in the ship's hold. ' The Cause. It is interesting to recall that the apples referred to in the case were the first imported Australian apples affected with brownheart to come under the personal ' observation of the Food Investigation Board in England. Previous' to that Dr. Franklin Kidd, D.Sc, and Dr. Cyril West, D.Sc, had been carrying out a series of storage tests, and they were responsible to applying the term'"Brownheart" to the disease under review. • The condition wa3 investigated and found'to be due, not to infection by bacteria or •aoulds, but to some defect 1 in'those .living processes which the apple, as a live thing, must' constantly manifest. Tlie storage tria.ls, in the course of which brownheart appeared, were carried out; with tiie object of finding a-simple and! a . cheap method by which the small grower could hold his.apple crop.' .The retarding effect upon the ripening Of the apples of increased carbon dioxide, and decreased oxygen in the air, was. tried, and from the records of the experiments the conclusion was drawn that brownheart was due to too much carbon flioxide, combined with too little oxygen. The apple, as- a live thing, breathes, and brownheart is the sign of a form of suffocation. The shipment of apples .round w-hich the present law case revolves, was in.a very bad condition when it reached.England, as numerous photographic records show. After obtaining a sample of the diseased fruit, the Investigation Board expressed the opinion that the condition was similar to that which had been observed in the course of one of the trials previously made, known as the gas-stor-age trial. No parasitic organism Could be isolated from the' affected part? of the apples. Tt was therefore' stated by the board that if the condition's of. storage in the holds were such" as to allow an accumulation of carbon dioxide aboy<> a certain, danger limit, combined with a corresponding, decrease of the oxygen percentage, the occurrence of an abnormal condition of ' the apples, similar, to those submitted to the board, might be expected. Investigations Begin. In the following year, 1022; the prevalence of the brown heart condition in apples imported from Australia began to attract general attention and to arouse anxiety among those connected with the trade. The assistance of the Food Investigation Board was-sought by Mr. F. E. Pear.cc. of the Overseas Farmers' Co-operative Association. It was pointed out that little advance could he made except by undertaking,a thorough examination of the conditions obtaining in the holds carrying apples, especially with regard to the gases present, and that such an examination should be conducted, over. . the whole period from the time the apples were stored to the time they left the ship. As a first step, arrangements were made for the board to'carry out a'preliminary examination of the-gases in' the holds of three vessels carrying apples on their arrival in England. Conclusions. The evidence gained by the board indicated clearly that apples which remained free from blemish when stored in air (21 per cent oxygen,- 0 per cent car- j lion dioxide) developed brown heart when stored in atmospheres containing percentages of carbon dioxide above a certain • danger limit, the presence- Of oxygen being essential to its. appearance. Tt did not. occur in the presence of'oxygen. Below the danger ' limit oxygen tolerated' carbon dioxide and low oxygen percentages without injury, and such conditions might be employed to obtain a beneficial retardation of ripening in storage. It was. shown.that brown heart might occur at any stage in the storage life of the fruit, and that the conditions causing it.'could produce their effect -in a short time. Low temperatures increased the susceptibility of the fruit and varieties and ...even, .individual apples differed markedly in their susceptibility to the disease. , It was also shown that the occurrence of. brown heart under the influence'; of carbon dioxide could not be prevented. by artificially maintaining a high oxygen concentration. The danger limit of carbon dioxide differed for different varieties, and at different storage temperatures, and possibly also for different stages 'of ripeness and for different concentrations of oxygen. • • Summary. In summing up the board said:'(a.) The evidence gained during the' investigations of the ships' holds indicated that the damage to the cargoes" 'was brought about by excess of carbon dioxide; (b) excess of carbon dioxide was due to insufficient ventilation, especially during the first few days after the warm fruit was loaded; '(c) pr.ecooling lessened the danger 'of excessive accumulation of carbon-dioxide when no ventilation, was provided, and the atmos- I phere of the hold was not circulated; (d) forced circulation of the hold atmospheres incidentally caused considerable ventilation, but, apart from that, there was no evidence in favour of forced air circulation as against the closed , hold without fans: (c) the amount of ventilation necessary to keep down the carbon dioxide was relatively small;' (f)' an j extended investigation of hold atmospheres throughout the voyage should be j undertaken, especially in the case of i dosed unveiuilated holds, to ascertain { why, in some eases, carbon dioxjde i accumulates in the holds more than in i others. . - j The report concluded hy stating that I the possibilities of regulating ventila- | tion so as to utilise the retarding effect I upon the ripening of,.fruit, of carbo'h ; dioxide and subnormal oxygen within | their, safety limits "of concentration, in j order to supplement the action of low temperatures in the overseas transport i of fruits, should be investigated, and ' tjiat- instruments by means of which j' the engineers can" ascertain the percien- ! tage .of carbpn. dioxide and oxygen'in the holds should be • developed ■ and 'employed, j