Food Science and Technology Department


First Advisor

Mary-Grace Danao

Second Advisor

Byron Chaves

Date of this Version

Spring 4-29-2022


Cancio, L.P.M. (2022). Evaluating the Microbial Quality and Use of Antimicrobials in Raw Pet Foods. [Master's thesis, 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 and Technology, Under the Supervision of Professors Mary-Grace Danao & Byron Chaves. Lincoln, Nebraska: April 2022

Copyright © 2022 Leslie Pearl Mansilita Cancio


Raw meat-based diets (RMBDs) are emerging pet foods that pose food safety risks because of the potential presence of pathogens that could cause illness to humans. In this research, the microbial quality of select RMBD products sold by pet food companies online and the use of chemical antimicrobials to reduce the microbial load in chicken liver, a common RMBD ingredient, were evaluated.

Ground meat blends and livers from four animal species (beef, pork, chicken, turkey) were purchased from four online companies that delivers directly to consumers through parcel businesses. Products were procured at three different times during one year and were assessed for their microbial quality, specifically aerobic plate count (APC), lactic acid bacteria (LAB), yeast and molds (Y&M), Enterobacteriaceae (EB), Salmonella spp., Escherichia coli, and Listeria spp. Overall, the microbial quality of the products were poor with some having high levels of indicator microorganisms that exceed acceptable levels of hygienic food criteria, e.g., APC (3.1 %; 2 out of 65) and EB (21.5 %; 14 out of 65). Presumptive Salmonella, generic E. coli and Listeria colonies were also detected in 33.8, 96.9, and 98.5 % of the samples, respectively. All four B2C companies missed at least one required information on their product labels, as well as safe food handling and storage instructions.

The effect of immersing and agitating chicken livers in peracetic acid (PAA, 450 ppm), cultured dextrose fermentate (CDF, 1.5 % w/v) and buffered vinegar (BV, 1 % w/v) on the reduction of Salmonella spp. and aerobic bacteria and meat color was investigated. All treatments [including distilled water (control)] resulted in significant reductions in Salmonella counts (p < 0.05). PAA resulted in the highest numerical Salmonella reduction from Day 0 (0.65 ± 0.12 log) to Day 14 (1.31 ± 0.12 log), although there were no significant differences in log reductions compared to control, signaling that immersion and agitation alone can reduce Salmonella. BV was the most promising in inhibiting the growth of aerobic bacteria – BV inhibited growth to Day 7, while PAA and CDF inhibited growth until Day 3 only.

Advisors: Mary-Grace Danao & Byron Chaves