200 BACTERIA, YEASTS, AND MOLDS 



the food. They do not live in the body, nor do they pro- 

 duce any definite bacterial disease. The effects are due 

 simply to the products of decomposition which have been 

 developed in the foods by certain kinds of bacteria. 



These troubles are much more common than we are apt 

 to realize. Since bacteria grow best at high temperatures, 

 it is not surprising to find more. cases of food poisoning in 

 warm weather. It is not an infrequent occurrence to have 

 a general poisoning follow any one of the innumerable 

 banquets held in our communities. Hundreds of cases 

 of intestinal trouble occasionally follow such banquets. 

 The illnesses resulting are rarely serious, but temporarily 

 they produce great inconvenience and trouble. They are 

 due to the development of ptomaines in some food prod- 

 ucts, since almost any of the putrescible foods which come 

 upon our tables may, in warm weather and under certain 

 circumstances, undergo a type of putrefaction which gives 

 rise to these poisonous ptomaines. When this occurs pto- 

 maine poisoning is quite likely to follow the use of the 

 foods. Such ptomaines are known to be developed quite 

 readily in materials that have been preserved in cold stor- 

 age and then removed to warm rooms. Hence it is desir- 

 able to consume cold-storage material as soon as possible. 

 It is almost certain that a large part of the summer 

 diarrhoea so common in warm weather is due to poison- 

 ous decomposition products developed in some of our foods, 

 milk being particularly likely to cause such trouble. 



Unfortunately we know very little concerning the con- 

 ditions under which such poisonous materials appear. 

 Not all bacteria produce them, and it is only rarely that 

 food is thus rendered unwholesome by bacteria. We 



