EXPERIMENT STATION REPORTS. 183 



described aliove had developed. I had Mr. Small plate out this material 

 by the loop dilution method. He isolated six cultures, which were inoculated 

 alone and with Bact. lactis acidi into sterile milk, the Bad. lactis acidi being 

 inoculated 24 hours after the other organisms had been inoculated. All of 

 these organisms produced off-flavors either alone or in conjunction with Bact. 

 lactis acidi, but two of them, which are undoubtedly identical, reproduced the 

 pe<'iiliar flavor mentioned above. This organism is a very short oval rod, 

 in fact it is almost a coccus. It i^roduces a small, round, white, elevated, 

 glistening, surface colony and a small, round, grey, dull, sub-surface colony. 



VII. Examination of Pink Buttermilk. 



Some pink buttermilk was sent in for a bacteriological examination. A 

 chemical examination had failed to show any cause for the red color, which 

 appeared sporadicall^y. Upon culturing, a yeast and Bact. lactis acidi were 

 found, although a microscopic examination of the buttermilk itself showed 

 the presence of rod shaped bacteria and the usual Bad. lactis acidi. In- 

 oculation of the yeast alone and in combination with Bact. lactis acidi failed 

 to reproduce the color. 



VIII. Off-flavor in a sample of milk. 



A sample of milk was brought to the laboratory by a consumer, who stated 

 that the milk frequ(>ntly had a disagreeable flavor and odor. Probably the 

 term "sickish" would apply as well to this as to the cream described above 

 under VI. The odor was similar to that of a cow's breath. Among other 

 organisms isolated from this milk was a very small organism. It was a short 

 rod, almost short enough to be called a micrococcus. It produced a light 

 3'ellow, soft surface colony. This, when inoculated into sterile milk, pro- 

 duced a putrid, sickish flavor and odor. 



IX. Milk suspected of making school children sick. 



Two samples were brought to the laboratory, one being milk of that day 

 and one the milk of the previous day. Both milks were plated and the plates 

 counted. The fresher milk had a bacterial count of 690,000 colonies per cc. 

 and the older milk a count of 5,600,000 colonies per cc. A study of the flora 

 revealed the fact that it was not that of normal milk. The plates on 

 which the counts had been made had a very putrid odor. No further work 

 was done with these samples. 



X. Yeasty Cream in a Creamer rj. 



A sample of cream was sent to the laboratory by a farmer's co-operative 

 creamery association to determine the cause of a yeasty flavor and a foamy 

 condition of the cream. Microscopic examination revealed the presence of 

 enormous numbers of yeast cells and organisms resembling Bact. lactis acidi in 

 microscopic appearance. The company requested me to visit their plant. 

 I found everything apparently in a sanitar}^ condition at the plant so a visit 

 was made to the patron bringing the yeasty cream. It was found that he 

 was not making anj^ attempt to sterilize his utensils or to cool his cream. 

 The cream was pooled from day to day and delivered twice a week. The 

 farmer was told how to sterilize his utensils and cool his cream. Favorable 

 results were reported. 



In connection with the research work on the Adams Fund Project lb, I 

 have been studying, as I proposed to do last year, the microflora of off- 

 flavored butters, some of Avhich were obtained from the United States De- 

 partment of Agriculture Inspector in Chicago and some were butters from 

 various sources including some experimental butters. About 200 such cul- 

 tures have been isolated and are being studied as to their ability to produce 

 off-flavors in sterile whole milk. It is planned to study these organisms and 



