Comparison of Four Methods of Isolating Salmonellae from Foods, and Elaboration of a Preferred Procedure

Abstract

SUMMARY From comparative study of four methods of isolation of Salmonella from egg products, of six enrichment broths and five selective media, and of several secondary technical operations, a recommended scheme for isolation of salmonellae from foods was devised and shown to be effective for diverse foods containing as few as 0.15 salmonellae per g, even in the presence of extreme coliform and other bacterial contamination.

Efficiency of Selenite Cystine and TT Enrichment Broths for the Detection of Salmonella

“…There is considerable disagreement about the preferred medium. Selenite cystine was found to be the preferred medium for eggs (Montford & Thatcher 1961), poultry feed (Huhtanen & Naghski 1972), dressed turkeys (Yamamoto et al 1961) and broiler carcases (Cox & Mercuri 1978). TT is recommended by the United States Department of Agriculture (USDA) for isolation of salmonellas from raw meat products (Anon.…”

“…That many different factors affect the recovery of salmonellas from foods may help explain such different recommendations. The type of food or feed being tested (Silliker & Taylor 1958;Galton et al 1968), the number of salmonellas present in the sample (Taylor & Schelhart 1968;Cox & Mercuri 1978), and the type of competing bacteria present (Montford &Thatcher 1961;Edel & Kampelmacher 1969;Hugues et al 1978) and whether or not pre-enrichment is used (Taylor & Silliker 1962) are all factors to be considered in determining which enrichment broth is preferable. Time (Anon.…”

A Comparison of Various Methods for Recovery of Salmonella Derby from Egg Shell Surfaces ,

“…More frequently though the greater restriction of the BGS agar did not allow "typical" colonies to develop for organisms which gave "typical" colonies on BG agar. Montford and Thatcher (1961), after comparing 4 methods for detection of Salmonella in food products, recommended SFC enrichment and streaking on BGS agar. From the results of the trials presented here with recovery of 5. derby from egg shells, it appears that a lactose broth preenrichment for 16 hr.…”

Occurrence, prevention, and monitoring of microbial quality loss of foods and dairy products

“…Adequate restoration 1815 and overgrowth by nonsalmonellae 18 ' 6 •' 8 ' 7 always have to be weighed against each other.…”