Reduction of Campylobacter on Chicken Livers Using a Low Acid Processing Aid

The objective of this study was to evaluate the reduction of Campylobacter in livers treated with a low pH processing aid, CMS PoultrypHresh with and without a surfactant (PoultrypHresh Plus). Chicken livers (n=36) were obtained from a local grocery; 13 livers were used in each of the two experimental treatment groups and 10 livers were used as untreated controls. Each liver was individually surface inoculated with a cell suspension of approximately 10⁸ cells of a gentamicin resistant C. coli marker strain in 0.1 mL of phosphate-buffered saline. Cells were allowed 5 min to attach prior to treatment. Thirteen inoculated livers were individually placed into separate sterile specimen cups containing 100 mL of PoultrypHresh or PoultrypHresh Plus. Livers were subjected to a 15 s non-agitated dip before being removed and allowed 5 s to drain. Each liver was placed into an individual sterile specimen cup with 50 mL of buffered peptone water and hand shaken for 60 s. Untreated controls were treated as experimental samples, without undergoing any type of treatment dip. Rinsates were collected from each liver, serially diluted and plated onto Campy Cefex agar with 200 ppm gentamicin. Plates were incubated for 48 h at 42°C microaerobically (5% O₂, 10% CO₂, 85% N₂); colonies were counted and the cfu/mL was log transformed. On untreated livers, mean recovery was 5.51 log₁₀ CFU/mL, using PoultrypHresh a 1.66 log reduction (97.8%) was observed compared to untreated livers. With PoultrypHresh Plus there was a 2.16 log reduction (99.3%). This study demonstrated that the use of PoultrypHresh and PoultrypHresh Plus reduced numbers of C. coli on the surface of chicken livers by greater than 97.0%. No change in appearance was noted.