26 MASS. EXPERIMENT STATION BULLETIN 426 



SUMMARY 



L Its spectacular nature and high mortality give botulism a place out of 

 proportion to its frequency as a cause of death. 



2. Almost without exception botulism outbreaks are caused by carelessness 

 and the use of faulty canning techniques. Water-bath processing and open- 

 kettle canning are responsible for many outbreaks. 



3. Home-canned string beans, corn, greens, asparagus, and beets are foods 

 which have been largely responsible for botulism outbreaks. Many factors, 

 some unknown, probably contribute to the low incidence of botulism from home- 

 canned foods. 



4. Botulinum organisms are widely distributed in nature and there is no 

 evidence that they are confined to certain geographical areas. 



5. The presence of decayed plant material favors the growth and develop- 

 ment of the botulinum organism and for this reason the recommendation that 

 only fresh sound products be used in home canning assumes an increased impor- 

 tance. 



6. Botulinum toxin, if present in home-canned foods, may be destroyed by 

 boiling the product for 10 to 20 minutes, depending upon the nature of the 

 product. 



7. Non-acid foods canned without a pressure canner or in a pressure canner 

 incorrectly used should never he tasted before they are boiled. 



8. Never taste any canned foods having a disagreeable odor or showing 

 evidence of spoilage. 



9. The addition of an acid, such as vinegar, to home-canned foods which 

 contain botulinum toxin may increase the potency of the toxin. This may have 

 a practical significance when such products as string beans are used for salads 

 without being heated after the jar is opened. 



10. Little is known regarding the effectiveness of botulinum antitoxin so far 

 as human cases are concerned. Available evidence would indicate that it is 

 effective if administered soon after consumption of the toxic foods. 



IL CI. botulinum can grow in many of the foods commonly canned at home. 

 Frequently sufficient toxin to cause illness or death may be produced in canned 

 foods before the appearance of the container or the food gives any warning of its 

 dangerous nature. 



12. The acidification of home-canned foods in order to reduce required process 

 times is not generally recommended. 



13. A toxin may develop in home-canned foods even after long months of 

 storage. It is recommended that home-canned foods be stored at a low tempera- 

 ture in order to retard or prevent the growth of viable organisms which might be 

 present in the jar. 



14. In some instances other spoilage bacteria may grow in jars of underproc- 

 essed food and inhibit or retard growth and toxin formation by CI. botulinum. 

 In many such cases the food would be obviously spoiled from appearance and 

 would not be eaten. 



15. Botulinum toxin may be produced in canned fruits and tomatoes if a 

 mold or yeast growth occurs which provides a favorable environment for the 

 development of CI. botulinum. Such products, when moldy, should not be eaten. 



