66 CITY MILK SUPPLY 



workers mentioned by him have collected from literature somewhat over 

 500 epidemics of typhoid fever that were milk-borne. In the United 

 States apparently the first recorded outbreak of typhoid fever that was 

 attributed to milk was that at Allegheny City, Pa., in 1882 but it was 

 not till about 1889 that the reporting of such epidemics became common. 

 Trask's own list is composed of 179 epidemics of which 107 were in the 

 United States, 43 in Great Britain, three in Continental Europe, three in 

 Australia, one in New Zealand and two in Canada. There are several 

 ways of accounting for the preponderance of cases in this country but the 

 fact that raw milk is more generally used here than abroad is outstanding. 



Typhoid fever may be transmitted in milk products as well as in whole 

 milk. In Kober's list of epidemics there are three that occurred in 

 Ireland during 1892-96, that were conveyed by skim-milk returned to 

 farms from creameries. In some cases whole milk was infected on the farm 

 of patrons and was mixed with that of others at the creamery while in 

 other instances the milk was infected by creamery employees. The group 

 of cases is interesting for in these days when the attempt is being made 

 to persuade legislatures to protect cattle and hogs from foot-and-mouth 

 disease and tuberculosis by enacting laws requiring the pasteurization 

 of skim-milk and whey at creameries and cheese factories before its 

 return to the farm, additional force is lent the argument by pointing out 

 that such laws would also protect human beings from contagion. In this 

 country Sedgwick in 1894 traced an epidemic in Marlboro, Mass., to skim- 

 milk from a creamery. 



The experiments of Mitchell show that B. typhosus can be recovered 

 from inoculated frozen cream after 3 weeks or more. Ice cream has been 

 held responsible for typhoid epidemics ; four have been recorded in Great 

 Britian and two in the United States. The first of those in this country 

 was reported by Horton from Montclair, N. J., in 1894. 



Butter is recognized as a possible medium of transmission of typhoid 

 fever but there seem to be no recorded epidemics due to it. Bruck 

 infected milk with B. typhosus, separated it and was able to find the or- 

 ganism 10 days thereafter in both the buttermilk and cream. In butter 

 made from this cream he recovered the bacillus after 27 days. Other 

 workers have obtained similar results. Typhoid fever germs certainly 

 live long enough in butter for them to reach the consumer in a virulent 

 condition so that if butter is made from infected milk or cream, typhoid 

 cases may be expected among those who eat it. However, there are several 

 reasons that diminish the probability of butter becoming a distributor of 

 typhoid fever. In the first place, it should be recognized that the process 

 of manufacture plays a part. Butter may be made from pasteurized 

 cream, from sweet cream or from sour cream, it may be salted or unsalted. 

 Butter from pasteurized cream is perfectly safe if the pasteurization has 

 been properly done and the cream is not subsequently infected. Unsalted 



