A bacterial composition that inhibits E. coli O157:H7 growth by as much as 93% and Salmonella growth by as much as 97%, together with commensurate inhibition rates against the Big-Six Escherichia coli strains referred to as the non-O157 STECs that include E. coli O121:H19; E. coli O45:H2; E. coli O103:H11; E. coli O145, E. coli O26:H11; and E. coli O111. The composition is constituted of various combinations of the following four unique pathogen-inhibiting bacteria: (1) Lactobacillus animalis strain MB101; (2) Lactobacillus animalis strain MB102; (3) Enterococcus faecium strain MB505; and (4) Pediococcus acidilactici strain MB902. Each of the discovered bacteria is deposited with the American Type Culture Collection (ATCC) and respectively has an individual ATCC Accession Number.