112 MODIFIED MILK AND MILK PRODUCTS 



(c) Sweetened condensed separated milk. 



(d) Unsweetened condensed separated milk. 



Bacteria are present in all varieties of condensed milk, but 

 in relatively small numbers, the method of preparation being 

 sufficient to eliminate most of the bacteria present in the 

 original milk. The following figures have been recorded : 

 230 to 70,940 per c.c. by Heggs, 130 to 20,000 per gramme by 

 Klein, 20,000 to 120,000 per c.c. by Dold and Garratt. Bold 

 and Garratt 1 found B. colt and B. enteritidis sporogenes absent 

 from I c.c. in all the 19 samples examined, but streptococci 

 were found in I c.c. in 8 cases (32 per cent.) and in o - i c.c. in 

 3 cases. Pathogenic organisms could not be detected in any of 

 the samples, either by direct examination or animal inoculation. 



Gordon and Elmslie 2 examined 15 different brands of con- 

 densed milk, and found none of them sterile. Streptococci 

 with characters similar to those found in milk were present in 

 all the II sweetened samples. These investigators concluded 

 that during the process of condensing unsweetened milk, sterility 

 is secured, the organisms found being subsequently introduced 

 from the air, but that in the condensing of sweetened milk 

 sterility is not attained, some at least of the organisms in 

 the original milk surviving the process of condensation. No 

 organisms of the B. coli group were isolated from any of their 

 samples. 



Delepine 2 carefully investigated the resistance of tubercle 

 bacilli to the processes involved in the preparation of condensed 

 milk, and found that although the original milk had been made 

 artificially highly virulent, after condensation its power to set up 

 tuberculosis in guinea-pigs was lost, all the tubercle bacilli being 

 killed. 



The analysis of condensed milk is mainly chemical, bac- 

 teriological examinations being seldom required. 



The bacteriological examination of condensed milk should 

 be on the same lines as for ordinary milk, the sample being first 

 thoroughly mixed with a definite quantity of sterile water. 



1 Journ. Roy. Inst. Public Health, 1910, XVIII, p. 794. 



2 Report by Dr Coutts to Local Govt. Board on Condensed Milk, 1911. 



