Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/17/2012
Publication Date: 6/30/2012
Citation: Carroll, J.A., Burdick, N.C., Ballou, M.A., Arthington, J.D. 2012. Phytochemicals as a preharvest pathogen reduction strategy. In: Callaway, T.R., Edrington, T.S., editors. On-Farm Strategies to Control Foodborne Pathogens. New York, NY: NOVA Science Publishers. p. 167-182. Interpretive Summary: Various chemicals found in plants, named phytochemicals, have been found to possess the ability to limit the growth of pathogenic bacteria. As the demand to remove sub-therapeutic antibiotics from livestock feedstuffs increases, there has been increased scientific effort to find non-antibiotic alternatives to enhance animal health and reduce the potential risk of increasing antibiotic-resistant bacteria. Additional efforts have also been focused on reducting pathogen load prior to harvest using phytochemicals. Although post-harvest methodologies have been employed to reduce pathogen transfer in the harvest facility, there is increasing interest in reducing pathogen loads in the live animals before harvest in order to further reduce potential pathogen contamination. Benefits of feeding phytochemicals have been demonstrated in several livestock species including swine, cattle, and pigs. The purpose of this chapter will be to acquaint readers with basic information regarding phytochemicals and to review what is now known about the ability of phytochemicals to reduce pathogen loads in livestock.
Technical Abstract: Phytochemicals are naturally occurring, non-nutritive chemicals produced by plants to limit pathogenic bacteria growth. Thousands of phytochemicals have been isolated from a variety of plants, and some have been documented to possess antimicrobial, antibacterial, and immunostimulatory properties. As there is an increasing demand from consumers to remove sub-therapeutic levels of antibiotics from livestock feeds in order to reduce the potential development of antibiotic-resistant pathogens, as discussed in an earlier chapter, there has been an increased scientific effort to identify non-antibiotic alternatives to enhance animal health and to reduce the potential risk of increasing antibiotic-resistant bacteria. Additionally, there have been efforts focused on the potential benefit of using phytochemicals as a means to reduce livestock pathogen loads prior to harvest, thus decreasing the potential for bacterial contamination during harvest and associated foodborne illnesses in humans. Although post-harvest methodologies have been employed to reduce pathogen transfer in the harvest facility, there is increasing interest in reducing pathogen loads in the live animals before harvest in order to further reduce potential pathogen contamination. The benefits of phytochemical addition to livestock feedstuffs have been demonstrated in several livestock species including swine, cattle, and poultry. While many phytochemicals have already been discovered and evaluated, it is expected that there will be a continued effort to identify even more phytochemicals as efforts continue to find feasible alternatives for sub-therapeutic levels of antibiotics in livestock production systems. This chapter will focus on some of the most characterized phytochemicals: citrus pulp and citrus peel, saponins, beta-glucan, flavonoids, and carotenoids, as well as other less-studied phytochemicals. The chapter concludes with a brief discussion on the potential toxic effects of phytochemicals in livestock.