Growth and survival of Listeria monocytogenes in vacuum-packaged ground beef inoculated with Lactobacillus alimentarius FloraCarn L-2.
A culture of the psychotrophic strain FloraCarn L-2 of Lactobacillus alimentarius was added to ground beef (pH 5.4) inoculated with two isolates of Listeria monocytogenes able to grow in refrigerated ground beef. The ground beef was vacuum-packaged and stored for 9 weeks at 4 degrees C. Populations of inoculated L. monocytogenes initially were 6.3 to 6.4 log10 CFU/g and increased to 7.4 log10 CFU/g in ground beef with no added lactobacilli. Addition of L. alimentarius L-2 or its antibiotic-resistant mutant SRL-2 reduced the final populations of L. monocytogenes to 4.3 or 4.1 log10 CFU/g, respectively. L. alimentarius L-2 did not produce bacteriocins or hydrogen peroxide in vitro. The antilisterial effect of L. alimentarius observed in laboratory media and ground beef is attributed to lactic acid (ca. 50 mM) produced by growing cultures.
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
B J
BJ
Juven
S F
SF
Barefoot
M D
MD
Pierson
L H
LH
McCaskill
B
B
Smith
D001430:Bacteriocins / Q000032:analysis*; D015169:Colony Count, Microbial; D003470:Culture Media; D004352:Drug Resistance, Microbial; D005511:Food Handling; D018857:Food Packaging / Q000592:standards*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000494:pharmacology; D007778:Lactobacillus / Q000187:drug effects / Q000254:growth & development*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D014618:Vacuum
D001430:Bacteriocins; D003470:Culture Media; D019344:Lactic Acid