Survival and destruction of Salmonella dublin and S. typhimurium added to Lebanon bologna was studied during manufacture of this sausage. During the aging period of salted cubed beef at 5 C, viable cell counts of S. dublin did not change over a 10-day period. Cell counts of S. Dublin were reduced 3 to 4 log cycles during the 4-day fermentation at 35 C; further reduction in the viable Salmonella count occurred during mellowing of the bolognas at 5 C. The number of S. typhimurium was usually reduced to an undetectible level before the end of the fermentation. Salmonella typhimurium was consistently more sensitive to the acid conditions of Lebanon bologna than was S. dublin. Introduction of an optional cooking step indicated that heating of bolognas to 51.7 C or above led to destruction of salmonellae. Unaged beef which was not inoculated with starter culture did not ferment and there was very little reduction in numbers of added salmonellae. Salmonellae were destroyed more rapidly in Lebanon bologna made from unaged beef with starter culture than in bologna made from aged beef (natural flora fermentation). Smoking also appeared to contribute to destruction of salmonellae. Four commercial Lebanon bolognas were tested for the presence of salmonellae but none were detected.
1Agricultural Research Service, U.S. Department of Agriculture.