PURE AND IMPURE FOODS. 



Edited by C. F. Langworthy, Ph..D. 

 Author of "On Citraconic, Itaconic and Mesaconic Acids," "Fish as Food," etc. 



"What a Man Eats He Is." 



OLIVE OIL MAKING IN CALIFORNIA. 



The most satisfactory method of making 

 olive oil is to crush carefully picked olives 

 as soon as possible after they are picked. 

 Bruised olives or those which are in the 

 slightest degree moldy yield an oil which 

 is inferior in quality. According to experi- 

 ments carried on at the California Experi- 

 ment Station, the extraction of oil from 

 fresh olives is somewhat troublesome, and 

 in order to facilitate the work it is custo- 

 mary to deprive them of a certain part of 

 their water before crushing. This partial 

 drying is also useful when it is necessary 

 to keep the fruit for some time before 

 crushing or to ship them to any distance. 

 It is generally done by placing them in lay- 

 ers not more than 3 inches deep, on trays 

 that are stacked in a dry, well-aired room, 

 protected from the wind and the direct rays 

 of the sun. The olives are turned over 

 daily, until they become well wrinkled. 

 This requires about 8 or 10 days, according 

 to the degree of temperature. If the par- 

 tially dried fruit can not then be crushed 

 immediately, it must be stored in a dark 

 room where the temperature does not rise 

 above 60 deg. F. There it may remain 3 

 or 4 weeks longer without any serious de- 

 terioration of the quality of the oil. In or- 

 der to hasten the drying process, artificial 

 driers, constructed on the same general 

 principle as the fruit or hop driers, are 

 sometimes used. The olives are placed in a 

 single layer on trays, and the drier is kept 

 at a temperature of about ^ 120 deg. F. If 

 the temperature rises above' 130 deg. F., the 

 quality of the oil will be impaired. The 

 drying takes about 48 hours, more or less, 

 according to the nature of the fruit. The 

 olives must be crushed immediately on re- 

 moval from the drier. 



The problem of keeping olives until they 

 can be crushed is an important one, as it 

 is practically impossible to gather all the 

 fruit of a large orchard just at the most 

 favorable time and to crush it all while 

 fresh. Numerous methods of solving this 

 problem have been tried, but only 3 have 

 been found which are free from serious 

 objections. Drying at a low temperature, 

 as already described, is that most generally 

 used. They have also been successfully 

 preserved temporarily in water. The olives 

 are placed in vats filled with fresh, pure 

 water, which is changed at least daily, as 

 is done in pickling. In mild climates not 

 subject to heavy frosts, perhaps the best 



185 



method is to leave the olives on the trees. 

 The quality of the oil deteriorates slightly 

 as the olives become overripe, but probably 

 less than in drying. It is usually stated 

 that the quantity of oil attains its maximum 

 at the time the olives are ready for pick- 

 ling, and that the apparent rise of oil con- 

 tent with further ripening is simply due to 

 evaporation of water. Recent investiga- 

 tions, however, show that there is a real 

 and even considerable increase of quantity 

 of oil per tree until February or March. 

 This adds another reason for leaving the 

 olives on the trees until they can be worked, 

 wherever the climate renders it possible. 



The crushing is still commonly done by 

 means of old fashioned stone mills. They 

 are slow, cumbrous and irregular in their 

 action. Moreover, almost all kinds of 

 stone that are used for these mills absorb 

 oil, which it is impossible to remove com- 

 pletely. This oil becomes rancid and taints 

 the olives that are being crushed. Crush- 

 ers with corrugated bronze or bronzed 

 metal rollers are now made that perform 

 their work in a satisfactory manner, break- 

 ing the flesh and pits thoroughly. As they 

 are all of metal they absorb no oil and are 

 easily cleaned. It is essential that the 

 flesh should be crushed thoroughly in order 

 to break the cells and permit the oil to be 

 pressed out. 



Some oil makers prefer to pit the olives 

 before crushing, in order to separate the 

 oil in the flesh from that in the pit. 



As soon as the olives have passed 

 through the mill or crusher they should be 

 pressed. For this purpose an extremely 

 powerful screw or hydraulic press is neces- 

 sary. The pressure must be applied grad- 

 ually. From the liquid, which runs out 

 first, with gentle pressure, is made the fin- 

 est grades known as "virgin oil." 



WHY POPCORN POPS. 



In early times popcorn was commonly 

 grown in small quantities on many farms 

 and in gardens for home consumption, for 

 it has long been a favorite food or food ac- 

 cessory with Americans. In recent years 

 there has been a tendency to depend on 

 the larger growers for popcorn and this 

 crop is now raised in some regions to a 

 large extent. For instance, a large grower 

 in Iowa has 1,000 acres annually planted to 

 popcorn, and in some regions in Nebraska 

 popcorn is practically the only crop grown, 



