Microbiological quality assessment and validation of antimicrobials against unstressed or cold-stress adapted Salmonella and surrogate Enterococcus faecium on broiler carcasses and wings

Abstract

This study aims to evaluate the microbiological quality and efficacy of antimicrobials to inactivate unstressed or cold-stress adapted Salmonella and Enterococcus on broiler carcasses and wings processed at a small USDA-inspected slaughter facility in West Virginia. The first part of the study included 42 carcasses that were pre- and secondarily-enriched in bacterial media followed by streak-plating onto XLT-4 and HardyCHROM™-agar Salmonella and confirmation using an API20E-kit. The aerobic plate counts (APC), Escherichia coli (ECC), total coliforms (TCC), and yeast/molds were analyzed on petri-films. The second part of the study included fresh broiler carcasses and wings that were inoculated with unstressed and cold-stress-adapted (4 °C, 7-day) Salmonella Typhimurium and Tennessee, and Enterococcus faecium ATCC 8459 (5.5 to 6.0 log10CFU/mL) and later dipped into peroxyacetic acid (PAA; 1,000 ppm), lactic acid (LA; 5%), lactic and citric acid blend (LCA; 2.5%), and sodium hypochlorite (SH; 70 ppm) for 30 s without (carcasses) or with 2-min drainage (wings). The surviving bacteria were recovered onto non-selective and selective agar to analyze the total microbial population, Salmonella and Enterococcus. APC, TCC, and Yeast/Molds were 2.62, 1.08, and 2.37 log10CFU/mL on broiler carcasses, respectively. A total of 30 and 40% of the carcasses tested positive for Salmonella spp. and E. coli (0.48 to 1.70 log10CFU/mL), respectively. For carcasses, antimicrobial reductions of cold-stress-adapted cells of Salmonella and Enterococcus were greater (P < 0.05) than the unstressed cells. For wings, cold-stress-adapted Salmonella were more (P < 0.05) sensitive to antimicrobials than unstressed cells; however, unstressed and cold-stress-adapted Enterococcus behaved similarly (P > 0.05). The reduction of Salmonella and Enterococcus on carcasses and wings increased in the order of SH ≤ LCA < LA < PAA and irrespective of unstressed or cold-stress-adapted cells. Applying post-chilling antimicrobial dipping treatments could be an intervention approach to control Salmonella on locally processed broilers. In addition, Enterococcus faecium could be a Salmonella surrogate for in-plant validation studies.

Comparing the Efficacy of Two Triple-Wash Procedures With Sodium Hypochlorite, a Lactic–Citric Acid Blend, and a Mix of Peroxyacetic Acid and Hydrogen Peroxide to Inactivate Salmonella, Listeria monocytogenes, and Surrogate Enterococcus faecium on Cucumbers and Tomatoes

“…Enterococcus faecium has been previously studied and validated as a potential Salmonella surrogate in almonds (Jeong et al, 2011), a balanced carbohydrate-protein meal (Bianchini et al, 2014), and pet foods (Ceylan and Bautista, 2015) during thermal activation processing. Our recent study also confirmed that E. faecium could be a non-pathogenic surrogate of Salmonella for in-plant antimicrobial validation studies on broiler carcasses (Lemonakis et al, 2017). To evaluate the suitability of choosing surrogate microorganisms for foodborne pathogens when exposed to antimicrobials, the surrogate should behave equally well or better (resistant to interventions) compared to the target pathogen in challenge studies (Adler et al, 2016).…”

“…Salmonella Typhimurium ATCC 14028, Salmonella Tennessee ATCC 10722, L. monocytogenes strains L2624 and L2625 (cantaloupe outbreak serotype 1/2b, donated by Dr. Joshua Gurtler, USDA-ARS, Wyndmoor, PA), and surrogate E. faecium ATCC 8459 were used in this study. Both Salmonella and L. monocytogenes strains were used in the previously reported farmers market produce safety projects (Li et al, 2017(Li et al, , 2018, and this strain of E. faecium has also been studied in WVU poultry meat projects (Lemonakis et al, 2017;Boltz et al, 2019). Salmonella, L. monocytogenes, and E. faecium retrieved from frozen stock cultures were streak-plated onto xylose lysine tergitol-4 agar (XLT-4, Hardy Diagnostics, Santa Maria, CA, USA), Modified Oxford agar (MOX, Hardy Diagnostics, Santa Maria, CA, USA), and BEA (Hardy Diagnostics, Santa Maria, CA, USA), respectively, and then incubated at 35 • C for 48 h to generate single colonies.…”

Inhibitory Activity of Natural Synergetic Antimicrobial Consortia Against Salmonella enterica on Broiler Chicken Carcasses

“…Carcasses were then treated by spray with 200 ml of the antimicrobial formulas including water, reuterin + lactic acid, reuterin + microcin J25, and peracetic acid. The procedure was repeated for a total of six carcasses per treatment (3 × 2 replicates; Lemonakis et al, 2017 ). The peracetic acid was a commercial product (CHINOOK, Sani-Marc Inc., Victoriaville, QC, Canada) prepared according to the manufacturer’s instructions.…”

Antimicrobial resistance associated with the use of antimicrobial processing aids during poultry processing operations: cause for concern?

“…It is worth mentioning that the antimicrobial efficacy of APA is mainly expressed as the log reduction in bacterial numbers (Bloomfield 2002). This antimicrobial activity is usually evaluated using classical bacterial culture methods, followed by the enumeration of bacterial colonies and their identification with biochemical testing (Wideman et al 2016;Lemonakis et al 2017). Recently, high-throughput sequencing has become a method of particular interest as a novel tool to assess changes in bacterial communities after APA use during poultry processing (Kim et al 2017;Handley et al 2018).…”

“…), representing the highest risk for public health among foods of animal origin. Human disease outbreaks attributed to poultry meat products costs about $2.4 billion annually in the United States (Lemonakis et al 2017). In Canada, it has been estimated that, in 2016, 10% to 37% of the nontyphoidal Salmonella infection cases in humans were attributed to the consumption of contaminated poultry and poultry products (Butler, Pintar, and Thomas 2016).…”