Evaluation of antibiofilm efficacy of essential oil components β‐caryophyllene, cinnamaldehyde and eugenol alone and in combination against biofilm formation and preformed biofilms of
            Listeria monocytogenes
            and
            Salmonella typhimurium

Growth inhibition of four strains of Escherichia coli O157:H7 (H1730, F4546, 932, and E0019) and Listeria monocytogenes (Scott A, 101, 108, and 310) by essential oil components (carvacrol and eugenol) solubilized in nonionic surfactant micelles (Surfynol 465 and 485W) was investigated. Concentrations of encapsulated essential oil components ranged from 0.02 to 1.25% depending on compound, surfactant type, and surfactant concentration (0.5 to 5%). Eugenol encapsulated in Surfynol 485W micelles was most efficient in inhibiting growth of the pathogens; 1% Surfynol 485W and 0.15% eugenol was sufficient to inhibit growth of all strains of E. coli O157:H7 and three of four strains of L. monocytogenes (Scott A, 310, and 108). The fourth strain, L. monocytogenes 101, was inhibited by 2.5% Surfynol and 0.225% eugenol. One percent Surfynol 485W in combination with 0.025% carvacrol was effective in inhibiting three of four strains of E. coli O157:H7. Strain H1730 was the most resistant strain, requiring 0.3% carvacrol and 5% surfactant for complete inhibition. Growth inhibition of L. monocytogenes by combinations of carvacrol and Surfynol 465 ranged between 0.15 and 0.35% and 1 and 3.75%, respectively. Generally, the antimicrobial activity of Surfynol 465 in combination with eugenol was higher than that for the combination with carvacrol. The potent activity was attributed to increased solubility of essential oil components in the aqueous phase due to the presence of surfactants and improved interactions of antimicrobials with microorganisms.

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Biofilm Development and Sanitizer Inactivation of Listeria monocytogenes and Salmonella typhimurium on Stainless Steel and Buna-n Rubber

Journal of Food Protection ◽

10.4315/0362-028x-56.9.750 ◽

1993 ◽

Vol 56 (9) ◽

pp. 750-758 ◽

Cited By ~ 153

Author(s):

AMY B. RONNER ◽

AMY C. L. WONG

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Salmonella Typhimurium ◽

Biofilm Formation ◽

Bacterial Biofilm ◽

Extracellular Matrices ◽

Nutrient Level ◽

Extracellular Materials ◽

Biofilm Development ◽

Nutrient Conditions

Biofilm formation by seven strains of Listeria monocytogenes and one strain of Salmonella typhimurium on stainless steel and Buna-n rubber was examined under two nutrient conditions. The type of surface, nutrient level, and organism influenced biofilm development and production of extracellular materials. Buna-n had a strong bacteriostatic effect on L. monocytogenes, and biofilm formation on Buna-n under low nutrient conditions was reduced for four of the seven strains tested. Buna-n was less bacteriostatic toward S. typhimurium. It inhibited the growth of several other pathogens to varying degrees. An ethylene propylene diamine monomer rubber was less inhibitory than Buna-n, and Viton rubber had no effect. The effectiveness of sanitizers on biofilm bacteria was examined. Biofilms were challenged with four types of detergent and nondetergent sanitizers. Resistance to sanitizers was strongly influenced by the type of surface. Bacterial biofilm populations on stainless steel were reduced 3–5 log by all the sanitizers, but those on Buna-n were resistant to these sanitizers and were reduced less than 1–2 log. In contrast, planktonic (suspended) bacteria were reduced 7–8 log by these sanitizers. Chlorine and anionic acid sanitizers generally removed extracellular materials from biofilms better than iodine and quaternary ammonium detergent sanitizers. Scanning electron microscopy demonstrated that biofilm cells and extracellular matrices could remain on sanitized biofilm cells and extracellular matrices could remain surfaces from which no viable cells were recovered.

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