Food Science and Technology Department


First Advisor

Byron D. Chaves

Date of this Version

Fall 12-2-2022


Emma, Nakimera, " Antimicrobial Efficacy of a Citric Acid/Hydrochloric Acid Blend, Peroxyacetic Acid, and Sulfuric Acid against Salmonella on Inoculated Non-conventional Raw Chicken Products" (2022). Dissertations, Thesis, & Student Research in Food Science and Technology. University of Nebraska-Lincoln


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Food Science & Technology, Under the Supervision of Professor Byron D. Chaves. Lincoln, Nebraska: November 2022

Copyright © 2022 Emma Nakimera


The utilization of non-conventional chicken parts as human food varies widely across countries. The high prevalence of Salmonella, especially in the giblets, poses a high risk to public health. Poultry processors have implemented multiple hurdle technology to reduce this gram-negative pathogen in chicken parts. This study was conducted to evaluate the antimicrobial efficacy of a commercial blend of citric acid/ hydrochloric acid (CP), peroxyacetic acid (PAA), and sulfuric acid (SA) in reducing Salmonella inoculated on two chicken giblets: livers and hearts. Chicken hearts and livers were inoculated (6 log CFU/ml of rinsate) by individually immersing them in a cocktail of five poultry-borne strains of Salmonella enterica subsp. Enterica each for 30 s achieving initial mean Salmonella recovery of 4.75 ± 0.10 and 4.69 ± 0.10 log CFU/g for chicken hearts and livers respectively. Inoculated chicken hearts and livers were treated by immersing into solutions (4 °C) containing PAA (500 ppm, 90 s), 5% v/v CP (pH 0.66; 30 s), 2% v/v SA (pH 0.93; 30 s), or distilled water (control; 90 s) and analyzed for survivors immediately after treatment (0 h), after one (24 h), two (48 h) and three (72 h) days of aerobic storage at 4 °C. The effect of these treatments on the growth of aerobic mesophilic bacteria and their effect on the color of the chicken hearts and livers were also investigated at the same time points. Results for Salmonella log reductions and aerobic plate count (APC) showed that there was no interaction between the type of antimicrobial treatment and storage time. Salmonella survivors recovered in chicken hearts following treatment (0 h) with PAA, SA, or CP were not significantly different (p < 0.05) from the control. However, SA-treated chicken hearts had significantly lower Salmonella counts than distilled water immediately after treatment. Unlike distilled water, all antimicrobials achieved greater than one-log reductions of Salmonella on both chicken hearts and livers, which indicated that immersing in antimicrobial solutions was more effective in reducing Salmonella. All treatments were effective in minimizing the growth of aerobic mesophilic microflora throughout the three days of storage with no significant differences (p < 0.05) in L*(lightness), a* (redness), b*(yellowness) values on the third day of storage in both chicken parts. Hence the results of the study showed PAA, SA, and CP may be used in the poultry industry as part of a multiple hurdle system to reduce Salmonella in non-conventional chicken parts.

Advisor: Byron D. Chaves