108 ABSTRACTS 



2. The season of the year apparently had Uttle influence on the 

 character of the bacterial content of the bulk oysters, a majority of 

 the samples containing a very large number of bacteria, many of which 

 belonged to the B. coli group. 



3. No definite correlation existed between the total number of bac- 

 teria and the number of gas formers found in the samples. 



4. The use of five or fifteen shell oysters for a sample did not materi- 

 ally affect the interpretation as to the sanitary quality of the sample 

 when judged by the U. S. Standards. 



5. On the basis of the bacteria developing on plain agar at 20°C., 

 on Endo medium at 37°C., and the presumptive test for B. coli, the 

 increase in bacteria in bulk oysters during 48 hours storage in the ice- 

 box cannot be interpreted as being due mainly to an increase in intestinal 

 bacteria. 



Normal Fermentation of Sauerkraut. Lester A. Round. 



The fermentation of sauerkraut was studied in two factories. In 

 the first factory, microscopic and chemical examinations were made 

 while in the second factory a bacteriological study was also made. 

 The microscopic examination showed that bacteria alone are concerned 

 with the proper fermentation. Wherever air came in contact with the 

 kraut or brine, as at the top of the vat, yeasts grew ver}^ rapidly after 

 the first week and produced a heavy foul-smelling scum which rapidh- 

 destroyed the acid. Analysis of fresh juice from a vat just being 

 filled showed the presence of five million bacteria, 80 per cent of which 

 were glucose fermenters. The remaining 20 per cent were mainly, 

 if not all, yeasts. The high count was due chiefly to the refilling of 

 tanks which had just been emptied and the walls served as a means of 

 inoculation with acid-producing organism. It was found that in the 

 first 24 hours the plate count would go up to about 100,000,000. Dur- 

 ing the first week it would go up gradually to 200,000,000 to 300,000,000. 



The rate of growth of bacteria and the rapidity of fermentation 

 varied directly with the temperature and were much slower in cold 

 weather than in warm. After reaching a maximum, the number of 

 bacteria gradually decreased until at the end of five weeks there were 

 present between four and ten million viable organisms. Lactose-bile 

 fermenting organisms were found in small numbers at the start. These 

 increased rapidly for the first few days and disappeared rapidly after 

 the kraut showed an acidity of plus 7.0. These organisms probably 

 came from the wagons, forks and shoes of the farmers who brought 

 in the cabbage. Examination of the interior of the cabbage-head 

 showed it to be sterile. 



Vats showing abnormal fermentation contained a different class of 

 organisms. A study of such vats indicated that bad fermentations in 

 a properly salted vat were due to the growth of unfavorable organisms 

 during the first few days before the normal acid flora had been able to 

 establish itself and produce sufficient acid to stop decomposition. In 

 the course of normal fermentation there was found to be a slight in- 

 crease in the temperature. 



