title: Treatment of Salmonella-Contaminated Eggs and Pork with a Broad-Spectrum, Single Bacteriophage: Assessment of Efficacy and Resistance Development.
abstract: Numerous studies have assessed the efficacy of phage-based methods to inhibit Salmonella contamination in food products. As with most antibacterials, bacteria can develop resistance to phage in vitro. Here, we applied a single broad-spectrum Salmonella phage, vB_SalS_SJ_2 (SJ2; 108PFU; MOI = 10), to Salmonella-contaminated meat and eggs to quantify the development of resistance in actual food matrices. Treatment with a single phage significantly reduced Salmonella Typhimurium contamination in both ground pork and liquid egg at various time points. Similarly, the same phage significantly reduced Salmonella Enteritidis in both food matrices. Efficacy was temperature dependent as larger reductions were seen at higher temperatures (21°C) versus lower temperatures (4°C) at 24 h. Following phage treatment, over 10,000 Salmonella isolates were examined for resistance to the treatment phage. The percentages of phage-resistant Salmonella (either serovar) recovered from phage-treated versus untreated pork did not differ. Conversely, significantly (p < 0.05) higher percentages of phage-resistant Salmonella Typhimurium (92.50% vs. 0.56% of control) and Salmonella Enteritidis (50.83% vs. 0.56% of control) isolates were observed in phage-treated versus untreated egg samples after incubation at room temperature for 48 h. Taken together, these data indicate that the food matrix may influence the emergence of phage resistance with resistance developing more rapidly in foods with less complex microbial communities. Future studies will focus on the impact the development of resistance in production and processing settings may have on the efficacy of phage treatments for longer term biocontrol of pathogens.
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Yingying
authors: Y
authors: Hong
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Kyle
authors: K
authors: Schmidt
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Danielle
authors: D
authors: Marks
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Samantha
authors: S
authors: Hatter
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Anne
authors: A
authors: Marshall
authors: 2 Department of Food Microbiology, Federal University of Viçosa , Viçosa, Minas Gerais, Brazil .
authors: Luiz
authors: L
authors: Albino
authors: 1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
authors: Paul
authors: P
authors: Ebner
mesh_terms: D000818:Animals; D058491:Bacterial Load; D001433:Bacteriolysis; D061046:Biological Control Agents; D002645:Chickens; D004531:Eggs / Q000191:economics / Q000382:microbiology* / Q000821:virology; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling; D005519:Food Preservation; D061353:Food Storage; D006358:Hot Temperature; D008460:Meat / Q000191:economics / Q000382:microbiology* / Q000821:virology; D050296:Microbial Viability; D012034:Refrigeration; D012478:Salmonella Food Poisoning / Q000382:microbiology / Q000517:prevention & control; D012483:Salmonella Phages / Q000502:physiology*; D012477:Salmonella enteritidis / Q000254:growth & development* / Q000302:isolation & purification / Q000821:virology; D012486:Salmonella typhimurium / Q000254:growth & development* / Q000302:isolation & purification / Q000821:virology; D017906:Siphoviridae / Q000502:physiology; D034421:Sus scrofa
chemical_list: D061046:Biological Control Agents
keywords: food matrices; phage resistance; phage therapy; single broad-spectrum phage