The 375 group and family outbreaks together involved 5,238 persons. While it is not probable that all the instances reported as due to food poisoning can properly be so considered, there is no doubt that the number recorded in the tables falls far short of the actual occurrences. In the past few years the writer has investigated several large food-poisoning outbreaks which have never been reported in the press nor received public notice in any way. There is reason to think that the majority of cases escape notice. Probably several thousand outbreaks of food poisoning in families and larger groups, affecting at least 15,000-20,000 persons, occur in the United States in the course of a year.
The assignment of causes indicated in [Table I] is of limited value. The tendency to incriminate canned food is here manifest. Proper investigation of the origin of an outbreak is so rarely carried out that the articles of food ordinarily accused are selected rather as the result of popular prejudice and tradition than of any careful inquiry.
Food Poisoning in the United States, October, 1913, to October, 1915
| Assigned cause | Group and Family Outbreaks | Individual Cases | Total |
| Meat | 40 | 35 | 75 |
| Canned fish | 29 | 35 | 64 |
| Canned vegetables | 27 | 34 | 61 |
| Ice cream | 31 | 22 | 53 |
| Fish, oysters | 17 | 31 | 48 |
| Cheese | 31 | 9 | 40 |
| Sausage and canned meat | 18 | 18 | 36 |
| Milk | 14 | 13 | 27 |
| Mushrooms | 12 | 7 | 19 |
| Fruit | 8 | 11 | 19 |
| Vegetables | 11 | 7 | 18 |
| Fowl | 12 | 4 | 16 |
| Salad | 9 | 5 | 14 |
| Contact of food or drink with metal | 12 | 1 | 13 |
| Miscellaneous | 29 | 55 | 84 |
| No cause assigned | 300 | 287 | 587 |
| 357 | 88 | 445 | |
| 657 | 375 | 1,032 |
Seasonal Distribution of Food Poisoning Cases, 1914-15 (Group, Family, and Individual)
| January | 90 | May | 63 | September | 76 |
| February | 66 | June | 108 | October | 96 |
| March | 75 | July | 99 | November | 96 |
| April | 79 | August | 96 | December | 88 |
There is no very striking seasonal incidence apparent in the figures here gathered ([Table II]). The warmer months seem to have a slight preponderance of cases, but general conclusions from such data are hardly warranted.