Frost—Bacteriological Control of Public Milk Supplies. 1337 
D. General Consideration of Results Obtained. 
When the results obtained from each grade and source are 
grouped and studied, certain interesting, and, it is believed, 
very important points are brought to light, so that it seems worth 
while to consider the points raised somewhat in detail. 
1. Raw Milks. The analyses of raio milks are grouped and 
shown in Table IV. It is to be noted here that the first three 
milks, A-, B. n and C x , which are to be pasteurized before market¬ 
ing, are much similar. The bacterial count is high, about 
2,000,000. B. coli, or its allies, are practically always present in 
quantities of 100 per c. c. Usually there are 1000 per c. c. and 
occasionally, at least, there are 10,000 per c. c. Spores of Bact. 
Welchii are generally present; frequently there is one such spore 
for each 2 c. c. of the milk, but on the average there are 4.2 to 
each 20 c. c. of the milk. Spores of organisms growing under aero¬ 
bic conditions are also present in considerable numbers. K and L. 
were raw milks to be sold as produced and the samples studied 
were from stores. They were apparently somewhat better milks. 
The high bacteria] count comes, no doubt, from recent multipli¬ 
cation since, aside from the rather high Bact. Welchii content, 
there is no evidence that these milks are badly contaminated. 
The milks marked F 1? F 2 , and F 3 are from a small 
town (15,000) and are very much cleaner than the city milks. It 
is worthy of special note that F x and F 2 came directly from the 
producer, while F a is a similar and sometimes the same milk 
which has gone through the bottling works with considerable 
detriment to the quality of the milk. 
E is a relatively small producer who is apparently producing 
quite a good quality of milk. 
2. Pasteurized Milks. The pasteurized milks (Table III.) are 
of two classes, those pasteurized in bulk and from milk produced 
without any special care, and those from milks belonging to the 
inspected grade and pasteurized in bottles. The first class, A 2 , 
B 2 and C 2 , all contain more bacteria than would be allowed by 
the Commission’s standard. Practically all of the samples con¬ 
tain B. coli in 1 c. c. lots, and some even show 100 per c. c. The 
number of resistant forms is high, showing, I believe, inefficient 
sterilization and cleanliness of the pasteurizing and bottling ap¬ 
paratus and utensils. The high content of Bact. Welchii is, of 
course, to be attributed to the contaminated condition of the raw 
milk. 
