xii. a. 2 Brill, Parker, and Yates: Copra and Coconut Oil 63 



calculated on the basis of the molded sample for demonstrating 

 the quantity of oil actually decomposed. 



MICROORGANISMS AND THEIR EFFECT ON COPRA AND COCONUT OIL 



Comparatively little attention has been given to the effect 

 of microorganisms on coconut oil. Walker 12 has called attention 

 to the fact that they do seriously affect the quantity and quality 

 of the oil in copra. However, his experiments were few and 

 devised primarily to show the action of the organisms on the 

 oil irrespective of the amount of moisture present in the copra. 

 When fresh coconut meat is exposed to the air, various fungi 

 make their appearance, and as the moisture content of the meat 

 becomes less, these fungi are succeeded by others. Certain fungi 

 always appeared on the fresh meat and others on fairly dry 

 copra, and so it seemed probable that each of the fungi con- 

 cerned was restricted more or less closely to a definite condition 

 of moisture in the copra. The life history of each of the more 

 important organisms was studied to determine whether the effect 

 on the oil caused by the different species of fungus might not 

 vary. Special attention was paid to the rate of growth, the 

 moisture requirements, and the effect upon the oil. 



Our early observations confirmed Walker's 13 statement that 

 two classes of plants known as bacteria and fungi are present and 

 may be concerned in the deterioration of copra. Very early in 

 the investigation we determined that bacteria normally play 

 only a very minor role in the deterioration of copra, since a 

 moisture content sufficiently high to favor bacterial growth is 

 not found in ordinary copra. Therefore the investigation has 

 not been concerned with the action of bacteria beyond a general 

 confirmation of Walker's conclusions that bacteria grow only on 

 fresh coconut meat or on copra, whose moisture is very high. 

 Furthermore they cause little if any loss of oil even under con- 

 ditions most favorable for their growth. Bacteria do seriously 

 affect the appearance of the copra and the quality of the oil, as 

 by their action they break the copra down into a slimy mass with 

 an offensive odor. However, the fungi play a much more im- 

 portant part in the deterioration of the oil in copra than do 

 bacteria. 



Copra containing less than 20 per cent of water is practically 

 free from bacterial action, and even above this moisture content 

 the deterioration caused by fungi is of far greater importance. 

 Not only are the moisture requirements of most of the fungi 



"Op. cit., 117. "Op. cit. (1906), 1, 135. 



