Addition of a surfactant to tryptic soy broth allows growth of a lactic acid bacteria food antimicrobial, Escherichia coli O157:H7, and Salmonella enterica.
OBJECTIVE
This study aimed to determine the survival and growth of Escherichia coli O157:H7 and Salmonella enterica subsp. enterica in a medium supporting the growth of a Lactic Acid Bacteria (LAB) food antimicrobial culture.


RESULTS
Foodborne pathogens and LAB were cultured individually in tryptic soy broth (TSB), tryptic soy broth supplemented with one g l(-1) Tween 80(®) (TSB-T80), and de Man, Rogosa and Sharpe (MRS) broth. Growth of E. coli O157:H7 and Salmonella was similar in TSB and TSB-T80 but was significantly less in MRS. Conversely, LAB growth was similar in MRS and TSB-T80 but was significantly less in TSB.


CONCLUSIONS
Supplementation of TSB with Tween 80(®) allows growth of LAB to levels similar to that observed with MRS but does not inhibit the growth of E. coli O157:H7 and Salmonella. We present the formulation of a medium useful in studies useful for evaluating competitive inhibition of foodborne pathogens by LAB in vitro.


CONCLUSIONS
This study reports the utility of TSB-T80 for the completion of in vitro competitive inhibition assays incorporating a Lactic Acid Bacteria food safety culture.
Texas AgriLife Research, Department of Animal Science, College Station, TX 77843, USA.
T F
TF
Cálix-Lara
T
T
Duong
T M
TM
Taylor
D003470:Culture Media / Q000737:chemistry*; D019453:Escherichia coli O157 / Q000254:growth & development*; D005516:Food Microbiology; D019344:Lactic Acid / Q000378:metabolism*; D007777:Lactobacillaceae / Q000254:growth & development*; D011136:Polysorbates; D019779:Salmonella enterica / Q000254:growth & development*
D003470:Culture Media; D011136:Polysorbates; D019344:Lactic Acid