Reduction of Escherichia coli O157:H7 by stimulated Pediococcus acidilactici.
This study was conducted to determine if stimulating the growth of meat starter culture (Pediococcus acidilactici) in a laboratory medium (Brain Heart Infusion broth +2.3% NaCl + 1.5% sucrose; LBHI) and during meat fermentation would control Escherichia coli O157:H7. In LBHI medium without P. acidilactici, the numbers of E. coli O157:H7 increased from 4.00 to 8.34 log10 cfu ml-1, whereas in the presence of P. acidilactici (approximately 6.0 log10 cfu ml-1) in LBHI, LBHIM (LBHI + 0.005% MnSO4), LBHIO (LBHI + 0.3 unit ml-1 Oxyrase), and LBHIMO (LBHI + M + O), the numbers of E. coli O157:H7 increased from 4.00 to 8.05, 7.50, 7.99, and 6.50 log10 cfu ml-1, respectively, after incubation at 40 degrees C for 15 h. During salami fermentation, the numbers of E. coli O157:H7 changed from 7.00 to 6.40 and 5.10 log10 cfu g-1 without and with P. acidilactici (approximately 7.0 log10 cfu g-1), respectively. Stimulated P. acidilactici by M, O, and MO further reduced the number of E. coli O157:H7 from 7.00 to 4.00, 4.80, and 3.65 log10 cfu g-1, respectively. The combination of MO was a better growth stimulator for P. acidilactici, which controlled E. coli O157:H7 in both systems (P < 0.05).
Kang
D H
DH
Department of Animal Sciences and Industry, Kansas State University, USA. kang@e-mail.marc.usda.gov
Fung
D Y
DY
D000818:Animals; D000898:Antibiosis; D002417:Cattle; D015169:Colony Count, Microbial; D003470:Culture Media; D019453:Escherichia coli O157 / Q000254:growth & development*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000494:pharmacology*; D008461:Meat Products / Q000382:microbiology*; D010105:Oxygenases / Q000494:pharmacology; D010376:Pediococcus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013431:Sulfates / Q000494:pharmacology*
D003470:Culture Media; D017895:Manganese Compounds; D013431:Sulfates; D010105:Oxygenases; C072755:Oxyrase; C039798:manganese sulfate