BACTERIOLOGICAL TECHNIC gi 



f. The colon bacillus should not be present in specified volumes of 

 drinking water, of milk and pharmaceuticals. If present in such vol- 

 umes, it indicates excessive sewage or other objectionable contamination. 

 The colon bacillus is motile in young broth cultures, forms no spores, is 

 gas- (dextrose broth cultures in fermentation tube) and indol-forming, 

 reduces nitrates to nitrites, does not liquefy gelatin and is not stained 

 by Gram's method. , 



g. Syrups of all kinds, unless very carefully prepared and carefully kept 

 to prevent fermentation, are apt to show numerous bacteria, yeasts and 

 molds. Any syrup showing signs of yeast fermentation (gas bubbles, 

 vinous odor) or moldiness, it not fit for use and should be rejected. The 

 attempt to render it usable by boiling, is unsatisfactory, furthermore the 

 changes produced by the organisms are always objectionable and cannot be 

 rectified by heating or by other methods of sterilization. 



h. Recent investigations have shown that many of the marketed 

 (bottled) mineral waters contain numerous bacteria, from 10,000 to 

 300,000,000 and more per cc. In some cases colon bacilli have been found. 

 These findings prove that in many instances the methods of bottling must 

 be careless or otherwise unsatisfactory. Undoubtedly the contamina- 

 cion is in some instances due to reused and inadequately cleaned and 

 sterilized containers and in other instances to impure and inadequately 

 sterilized mineral water. A popular opinion prevails that the chemicals in 

 the mineral waters are sufficiently germicidal to destroy bacteria but 

 this is not the case, 



G. Bacteria in Canned Fruits. — The work recently demanded by the 

 pure food laws (federal and state) has shown that such food substances as 

 canned fruits of all kinds, including jams, jellies, preserves, catsups, 

 tomato pastes, etc., are frequently highly contaminated with yeast cells, 

 molds ■ and their spores, and other higher fungi, and bacteria. It is, 

 however evident that the food products named may be kept quite free 

 from such contamination as may be seen from the examination of canned 

 food products prepared by the careful housewife. That manufacturers 

 may approximate the home condition is demonstrated by the fact that 

 factory products are found on the market, which are quite free from 

 contamination. 



Since wholesome ripe fruit contains yeast cells, bacteria and mold in 

 very small numbers only, and since most of these organisms are removed in 

 the various steps of the processing, as washing, peeling, steaming, etc., it is 

 evident that the finished factory product should, like the home-made 

 product, contain these organisms in negligibly small numbers only, pro- 

 vided, of course, that wholesome fruit is used. However, most of the 

 factory samples thus far examined have shown numerous dead yeast cells, 



