Inhibition of foodborne bacterial pathogens by naturally occurring food additives

In this study diacetyl (DI), benzaldehyde (BE), pyruvic aldehyde (PY) and piperonal (PI) were tested for activity against Yersinia enterocolitica, Listeria monocytogenes, Salmonella typhimurium, Bacillus cereus, Shigella flexneri, Aeromonas hydrophila, Escherichia coli O157.H7, Staphylococcus aureus, and proteolytic Clostridium botulinum spores. The minimal inhibitory concentrations (MICs) required to inhibit pathogens ranged from 0.05 to 7.81 mM. The only exception was C, botulinum which was least sensitive, with DI or PY MIC of 25 mM; the MIC of BE or PI was 125 mM. A 30 min 56.8C heat treatment, of the organism/inhibitor mixture, reduced the MICs of BE and PI by 50-87%, and 77% less PY was required to inhibit E. coli O157:H7. BE or PI reduced C. botulinum spore 80C thermal- and radio-resistance. To determine whether antibacterial plant components exist naturally at inhibitory concentrations, EtOH-extracts of asparagus (As), carrots (Ca), radishes (Ra), shallots (Sh), and turnips (Tu) were tested for antibotulinal activity. As or Ca extracts were antigerminative at 0.07%. When combined equal quantities of As and Ca were tested, less than or equal to 0.03% delayed germination, however Although no activity was observed when Pa and Sh were rest singly, 0.13% AsCaRa, AsCaRaSh or AsCaRaShTu combinations were inhibitory. These data indicate that the naturally occurring food additives may be employed to control the foodborne pathogens assessed in this study.