Feed pathogen control is a critical control point for Salmonella and other pathogens that compromise both food safety and production performance. Research analyzing multiple intervention strategies confirms feed contamination is both pervasive and persistent. Microbial-based interventions, postbiotics, bacteriophages, organic acid blends, heat treatment, and coarse grain diets demonstrate measurable effectiveness, while feed sanitizers provide both initial pathogen elimination and sustained recontamination protection.
Global Head of Poultry Nutrition & Health
Anitox
Feed represents a key critical control point for Salmonella and other pathogens that compromise both food safety and production performance. As diagnostic capabilities advance through whole genome sequencing and CRISPR Sero-Seq technology, the question shifts from whether feed can harbor dangerous serotypes, to which interventions can effectively control them while preventing recontamination.
FEED CONTAMINATION DYNAMICS
Research analyzing multiple intervention strategies confirms that feed contamination with Salmonella is both pervasive and persistent (Bourassa et al, 2018; Chaney et al, 2022; Vilá et al, 2009). Historical data mapping Salmonella prevalence through feed mills shows contamination levels beginning at 27% during ingredient reception, decreasing to 6.5% immediately post-pelleting, then nearly doubling to 12.9% before loadout (Nape 1968; Hacking 1978; Jones 1991, 2004; Davies 1997; Whyte 2003). This recontamination pattern demonstrates that effective pathogen control must address both initial elimination and sustained protection throughout distribution.
Research has demonstrated that Salmonella serotypes isolated during poultry processing link to those found in feed mills, with studies showing over half of processing plant isolates trace back to feed sources (Corry 2002; Shirota 2000), reinforcing the need for comprehensive feed pathogen management strategies.
TREATMENT EFFICACY: THE EVIDENCE BASE
Microbial-Based Approaches
Microbial-based interventions operate through distinct mechanisms. Probiotics establish competitive exclusion by colonizing gut niches and producing antimicrobial compounds that create unfavorable conditions for pathogen growth.
Studies have shown that probiotic interventions demonstrate measurable effectiveness against Salmonella. For example, Knap et al (2011) documented that Bacillus subtilis DSM17299 achieved 58% reduction in Salmonella-positive samples while reducing cecal loads by 3 log units over 42 days. Vilá et al (2009) reported complete elimination in broilers (0% versus 42% in controls) using Bacillus cereus var. toyoi.
Postbiotics deliver bioactive metabolites and immunomodulatory factors that enhance intestinal barrier function and stimulate protective immune responses without requiring live organisms. Chaney et al (2022) found Saccharomyces cerevisiae-derived postbiotics reduced cecal prevalence from 12.2% to 3.4% (p = 0.0006) in a trial involving approximately 112,800 birds.
Bacteriophages provide highly targeted antimicrobial action through species-specific lysis of Salmonella cells while preserving beneficial microbiota. A study assessing bacteriophage delivery via feed achieved up to 100% reduction in some treatment groups with statistically significant load reductions (Thanki et al 2023).
NON-MICROBIAL APPROACHES
Organic acid blends can show measurable benefits. Bourassa et al (2018) found formic acid treatment (4 kg/ton over 6 weeks) reduced cecal positivity to 0% compared to 17% in controls, while combination treatments achieved 35% versus 60% positivity rates.
Physical modifications to feed can also demonstrate efficacy. Santos et al (2008) reported coarse grain diets resulted in lower cecal Salmonella loads (3.8-3.9 log MPN/g) compared to fine grain diets (4.4 log MPN/g), suggesting feed particle size represents an underutilized control parameter.
Treatments—including heat treatment and organic acids— act in feed to provide effective initial pathogen reduction but offer limited protection against recontamination during handling, transport, and storage.
Heat treatment exemplifies this limitation. While pelleting at 80-85°C for 20-40 seconds reduces general microbial load, it fails to achieve Salmonella elimination and provides no residual protection. Even extended protocols (6 minutes at 86°C) cannot prevent post-processing contamination from the moment the feed cools post-extrusion and during handling between mill and feeder.
Organic acids face similar constraints. Despite bacteriostatic properties and demonstrated efficacy at high inclusion rates, they do not actively protect feed from recontamination occurring during ingredient transport, mill processing, finished feed storage, delivery to farms, and bin-to-feeder transfer.
FEED SANITIZERS: ADDRESSING THE PROTECTION GAP
Over 40 years of research evidences that feed sanitizers represent the only commercially available solution providing both initial pathogen elimination and sustained recontamination protection. Wales et al (2013) documented that formaldehyde-based feed sanitizers, such as Termin-8®, effectively reduced Salmonella contamination while preventing recontamination throughout extended storage periods.
Recent Animal Plant and Health Agency work demonstrated that formaldehyde-free feed sanitizer, Finio®, controlled Salmonella more effectively at 1 kg/MT inclusion rates than organic acid blends applied at 6 kg/MT—significant for both efficacy and cost-effectiveness (Gosling et al., 2021). Research by Dr. Haraldo Toro expanded feed sanitizer effectiveness beyond bacteria, demonstrating avian influenza virus inactivation within feed matrices.
Feed sanitizers provide protection extending at least 14 days post-application, addressing the recontamination challenge limiting other strategies. This protection window covers typical mill-to-consumption timeframes, ensuring pathogen-free feed delivery to food-producing animals.
IMPLEMENTATION AND SELECTION CRITERIA
Continuous feed sanitation throughout the production cycle provides greater protection than partial approaches, as benefits accumulate over time to suppress pathogens more effectively. Early application is especially important, since exposure during initial gut development can establish long-lasting colonization that is difficult to control later. Collaborative research between Anitox and Colorado Quality Research has shown that birds receiving sanitized diets during critical windows may be better able to withstand enteric disease challenges, with lower mortality, reduced lesion scores and improved performance—highlighting the value of sustained, cycle-long interventions.
When evaluating feed pathogen control options, producers should consider two fundamental requirements:
Efficacy: Different treatments demonstrate varying capabilities against target pathogens. While some reduce general microbial load, specific pathogen elimination requires targeted approaches with documented effectiveness against Salmonella.
Sustained Protection: The feed mill and the extensive feed distribution network create ongoing recontamination risks from the point of extrusion in the mill all the way through to the feeder. Interventions providing residual protection offer advantages over those effective only at application point.
Feed pathogen management represents a practical component of comprehensive food safety programs. Research demonstrates multiple intervention categories can achieve measurable Salmonella reduction, with varying effectiveness and protection duration.
Producers implementing feed pathogen control strategies should evaluate options based on demonstrated efficacy, practical application requirements, and ability to maintain protection throughout the distribution chain. The goal remains straightforward: Ensuring feed quality at the mill translates to feed safety at the feeder.
As the industry optimizes production efficiency while maintaining food safety standards, evidence-based feed pathogen management strategies provide valuable tools for achieving both objectives simultaneously.
References
1. Al-Nass, A. Y., Al-Zenk, S. F., Al-Saff, A. E., Abdulla, F. K., Al-Baho, M., & Mashaly, M. (2011). Zeolite as a feed additive to reduce Salmonella and improve production performance in broilers
2. Bourassa, D., Wilson, K., Ritz, C., Kiepper, B., & Buhr, R. J. (2018). Evaluation of the addition of organic acids in the feed and/or water for broilers and the subsequent recovery of Salmonella Typhimurium from litter and ceca. Poultry Science, 97(1), 64-73
3. Chaney, W., Naqvi, S. A., Gutierrez, M., Gernat, A., Johnson, T., & Petry, D. (2022). Dietary inclusion of a Saccharomyces cerevisiae-derived postbiotic is associated with lower Salmonella enterica burden in broiler chickens on a commercial farm in Honduras. Microorganisms, 10(6), 1123
4. Knap, I., Kehlet, A. B., Bennedsen, M., Mathis, G., Hofacre, C., Lumpkins, B., Jensen, M. M., Raun, M., & Lay, A. (2011). Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers. Poultry Science, 90(12), 2787-2796
5. Santos, F. B. O., Sheldon, B. W., Santos, A., & Ferket, P. R. (2008). Influence of housing system, grain type, and particle size on Salmonella colonization and shedding of broilers fed triticale or corn-soybean meal diets. Poultry Science, 87(3), 405-420
6. Thanki, A., Hooton, S. P. T., Whenham, N., Salter, M., Bedford, M., O’Neill, H. M., & Clokie, M. R. J. (2023). A bacteriophage cocktail delivered in feed significantly reduced Salmonella colonization in challenged broiler chickens. Emerging Microbes and Infections, 12(1), 2181578
7. Vilá, B., Fontgibell, A., Badiola, I., Esteve-Garcia, E., Jiménez, G., Castillo, M., & Brufau, J. (2009). Reduction of Salmonella enterica var. Enteritidis colonization and invasion by Bacillus cereus var. toyoi inclusion in poultry feeds. Poultry Science, 88(5), 975-979
8. Wales, A. D., Carrique-Mas, J. J., Rankin, M., Bell, B., Thind, B. B., & Davies, R. H. (2010). Review of the carriage of zoonotic bacteria by arthropods, with special reference to Salmonella in mites, flies and litter beetles. Zoonoses and Public Health, 57(5), 299-314
About Dr. Alastair Thomas
With a PhD in Microbiology from the University of Bath, Dr. Alastair Thomas is the Global Head of Poultry Nutrition and Health at Anitox, where he leads a worldwide team of technical experts across 68 countries. A microbiologist by training, he focuses on optimizing poultry gut health, feed hygiene, and biosecurity, with particular expertise in early-life microbiome development and its impact on bird performance. He has contributed extensively to advancing antimicrobial-free production practices by highlighting the role of feed as a critical control point for pathogens such as Salmonella, Enterobacter, and Clostridia. Widely recognized as a thought leader in the field, Dr. Thomas integrates scientific research with practical, data-driven solutions to help producers safeguard flocks, improve nutrient absorption, and unlock the genetic potential of birds.
