Effectiveness of a one-day procedure for recovery of Salmonella from milk powders.
A rapid procedure for enumerating Salmonella in milk powders was evaluated. Dry whole milk and instant nonfat dry milk were rehydrated, artificially inoculated with various numbers of Salmonella cells, and stomached. Test portions were then treated with Tween 80 and pancreatic trypsin, and incubated for 1 h at 30 degrees C. The incubated test portions were centrifuged at 10,000 x g for 15 min at 5 degrees C, and the resuspended pellets were plated on xylose lysine desoxycholate agar. The effectiveness of the procedure was expressed in terms of percentage recovery of the inoculum. The procedure, which was evaluated in 76 trials using 7 Salmonella serovars, recovered < or = 73% of the inoculum for half of the trials conducted. Its effectiveness was dependent on the serovar, level of inoculation, and type of milk powder used.
Hammack
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U.S. Food and Drug Administration, Division of Microbiological Studies, Washington, DC 20204.
Andrews
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Amaguana
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RM
June
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GA
Sherrod
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PS
D000818:Animals; D001431:Bacteriological Techniques; D003470:Culture Media / Q000737:chemistry; D008892:Milk / Q000382:microbiology*; D012475:Salmonella / Q000302:isolation & purification*; D013997:Time Factors
D003470:Culture Media