Antimicrobial activity of Microgard against food spoilage and pathogenic microorganisms.
Microgard, a commercially available fermented milk product containing antimicrobial metabolites, was a potent inhibitor for Gram-negative bacteria such as Pseudomonas, Salmonella, and Yersinia when 1% concentration was incorporated into agar media. Gram-positive Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes were insensitive to Microgard. Kluyveromyces marxianus, an unidentified black yeast, and Penicillium expansum were partially suppressed, whereas Aspergillus niger and a yogurt spoilage yeast were tolerant to 5% Microgard. Optimum activity of Microgard was at pH 5.3 and below; the concentration that gave complete inhibition depended upon the number of bacteria present as well as the genus tested. Blood agar base reversed the antagonistic activity of Microgard against Pseudomonas putida compared with plate count agar.
al-Zoreky
N
N
Department of Food Science and Technology, Oregon State University, Corvallis 97331-3804.
Ayres
J W
JW
Sandine
W E
WE
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000494:pharmacology*; D016123:Campylobacter jejuni / Q000187:drug effects / Q000254:growth & development; D003470:Culture Media; D003611:Dairy Products; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D005285:Fermentation; D005516:Food Microbiology; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development*; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development; D011549:Pseudomonas / Q000187:drug effects / Q000254:growth & development; D012762:Shigella dysenteriae / Q000187:drug effects / Q000254:growth & development
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D003470:Culture Media