Current Status of the Preharvest Application of Pro- and Prebiotics to Farm Animals to Enhance the Microbial Safety of Animal Products

Abstract

The selection of microorganisms that act as probiotics and feed additives that act as prebiotics is an ongoing research effort, but a sizable range of commercial pro-, pre- and synbiotic (combining pro- and prebiotics) products are already available and being used on farms. A survey of the composition of commercial products available in the United States revealed that Lactobacillus acidophilus, Enterococcus faecium, and Bacillus subtilis were the three most common species in probiotic products. Of the nearly 130 probiotic products (also called direct-fed microbials) for which information was available, about 50 also contained yeasts or molds. The focus on these particular bacteria and eukaryotes is due to long-standing ideas about the benefits of such strains, research data on effectiveness primarily in laboratory or research farm settings, and regulations that dictate which microorganisms or feed additives can be administered to farm animals. Of the direct-fed microbials, only six made a claim relating to food safety or competitive exclusion of pathogens. None of the approximately 50 prebiotic products mentioned food safety in their descriptions. The remainder emphasized enhancement of animal performance such as weight gain or overall animal health. The reason why so few products carry food safety-related claims is the difficulties in establishing unambiguous cause and effect relationships between the application of such products in varied and constantly changing farm environments and improved food safety of the end product.

Bacillus subtilis-Based Probiotic Improves Skeletal Health and Immunity in Broiler Chickens Exposed to Heat Stress

“…Bacillus subtilis, as one of the three most common species of probiotic products used in the United States [37,45], has been widely used in functional feed supplements, such as in several dairy and non-dairy fermented foods, for improving human health and well-being [46]. Similarly, Bacillus subtilis has been used as a probiotic with multiple functions in poultry [141].…”

“…Generally, probiotics confer a health benefit to chickens due to their positive effects on microbiota composition (restoring microbial homeostasis), mucosal barrier integrity (reducing gut permeability), and immune response (reducing inflammation). Bacillus subtilis is one of the most common bacterial species used in commercial probiotic products for farm animal production [37,38], including in poultry [39][40][41].…”

Biocontrol of the internalization of Salmonella enterica and Enterohaemorrhagic Escherichia coli in mung bean sprouts with an endophytic Bacillus subtilis

“…It is unknown if Pseudomonas is safe for human consumption. In contrast, B. subtilis bacteria are not known to be pathogenic; in fact, B. subtilis have been used as probiotics that are beneficial to human health (Khatri et al, 2016;Tompkins et al, 2010) and microbial safety of animal products (Joerger and Ganguly, 2017).…”

Bacillus spp. Probiotic Strains as a Potential Tool for Limiting the Use of Antibiotics, and Improving the Growth and Health of Pigs and Chickens

“…The main concerns regarding the safety of Bacillus strains are associated with their potential production of enterotoxins, the transfer of antibiotic-resistance genes and cytotoxicity against normal cells; two species of Bacillus, namely B. anthracis and B. cereus, are known as pathogens for humans (Cutting, 2011). The safety of the Bacillus species in livestock has been extensively reviewed elsewhere (SCAN, 2000;Joerger and Ganguly, 2017). In livestock, the main concerns are for B. cereus and B. licheniformis since they have been associated with an increase in mastitis in cattle and occasionally associated with bovine toxemia and abortions, respectively (Johnson et al, 1994;Parkinson et al, 1999).…”