Current advances in antimicrobial feed additives for terrestrial livestock: A systematic review

The transmission of zoonotic pathogens through animal feed and raw materials underscores the critical need for effective antimicrobial interventions. Following the prohibition of formaldehyde in several countries, there remains a significant gap in suitable alternatives for mitigating microbial hazards in feed. This systematic review evaluates research published between 2015 and 2025, focusing on the efficacy of various classes of antimicrobial agents, concerning organic acids, phytochemicals, and oxidizing agents, in animal feed and raw materials intended for terrestrial animals. A total of 23 relevant articles were identified and analyzed. The review highlights organic acids as broad-spectrum antimicrobial agents capable of reducing the prevalence of bacteria, viruses, and molds in in vitro feed and in vivo trials. While comparative studies on bacterial contamination are limited, formaldehyde-based mitigants continue to outperform organic acid-based mitigants in controlling viral contamination. Preliminary evidence suggests that integrating phytochemicals with organic acids may enhance the antimicrobial efficacy. Additionally, natural mitigants such as lactic acid bacteria (LAB), bacteriophages, wheat bran, and lignosulfonates have emerged as promising candidates for pathogen control. Nonetheless, ongoing inconsistencies in the existing results remain evident among these mitigants, underscoring the need for stronger scientific evidence. We also noted that the systematic review did not identify any studies evaluating oxidizing agents as antimicrobial mitigants. This absence highlights a potential research gap and suggests that future investigations into oxidizing agents may be warranted to address the growing need for effective antimicrobial solutions.