Interactions of organic acids with Campylobacter coli from swine

Abstract

Campylobacter coli is a bacterial species that is a major cause of diarrheal disease worldwide, and Campylobacter spp. are among the top 5 foodborne pathogens in the United States. During food production organic acids (OAs) are often used to remove bacteria from animal carcasses. The interactions of six OAs with 111 C. coli strains obtained from swine and retail pork chops were studied by determining the molar minimum inhibitory concentrations (MICMs) of the C. coli strains, and the pH at the MICMs. The Henderson-Hasselbalch equation was used to calculate the concentrations of the undissociated and dissociated OAs at the MICMs of the C. coli strains. The results for the 111 different C. coli strains obtained from different locations were treated as a single group for each OA since many of the C. coli strains behaved similarly to each different OA. Inhibition of C. coli was not dependent on pH or on the undissociated OA species, but C. coli inhibition correlated with the dissociated OA species. Therefore, if the concentration of the dissociated OAs decreases from optimum, one may then expect that C. coli bacteria would escape disinfection. The concentration of the dissociated OA should be carefully controlled in a carcass wash. We suggest maintaining a concentration of the dissociated acetic, butyric, citric, formic, lactic and propionic acids at 29, 23, 11, 35, 22 and 25 mM, respectively, when using a carcass wash with these OAs to remove C. coli bacteria. However, due to C. coli utilization of acetate, formate, lactate and propionate, these four OAs may not be the best choice to use for a carcass wash to remove C. coli contamination. Of the six OAs, citric acid was the most efficient at inhibiting C. coli.

Short Chain Fatty Acids Commonly Produced by Gut Microbiota Influence Salmonella enterica Motility, Biofilm Formation, and Gene Expression

“…strains found MIC values of 1.5% and 1%, respectively [24]. Campylobacter coli strains isolated from pigs had MIC values of 2048 µg/mL in most of the strains tested in the presence of butyric acid and propionic acid [25], lower than the MIC values observed in this study.…”

Interactions of organic acids with vancomycin‐resistant Enterococcus faecium isolated from community wastewater in Texas

“…) and Campylobacter coli (Beier et al . ), the levels of dissociated acids were closely correlated with the MIC M s of the bacteria in all studies. It also has previously been shown that a fully dissociable acid will cause the disintegration of the bacterial LPS layer (Alakomi et al .…”

“…But we have previously shown that Gram‐negative pathogenic bacteria are inhibited by dissociated OAs, and not by pH or the undissociated acids alone (Beier et al . , , , , ). Here, we investigate the effects of pH, undissociated OAs and dissociated OAs against Gram‐positive VRE to evaluate the characteristic of OAs that result in VRE inhibition.…”

“…The OA susceptibility studies were carried out similar to previous studies of other bacterial human pathogens (Beier et al . , , , , ). Briefly, Mueller–Hinton broth (50 μ l) (Becton Dickinson and Company, Sparks, MD) was added to each well in column 2 through the wells in column 12 of a 96‐well U‐bottom Greiner bio‐one microplate (#82050‐626; VWR, Houston, TX).…”

“…The ratio can then be used to calculate the concentrations of the undissociated and dissociated acid species when the molar concentration of the OA is known at the MICs (Beier et al . , , , , ).…”