Meeting Abstract
Food additives often have useful antimicrobial properties, which decrease the risk of ingesting pathogens in products such as dairy. Consumed food additives are eventually metabolized or excreted, but may impact the alimentary canal and the human gut microbiome during the digestive process. If preservatives inhibit the growth of unwanted bacteria in food products, then it is reasonable to infer that they can affect the growth of our microbiome as well. This study utilized a commensal species of bacterium from the human gut, Enterococcus faecalis, to test the hypothesis that exposing this bacterium to potassium sorbate (PS), will inhibit its growth. This preservative is classified as GRAS by the FDA, and is metabolized by fatty acid oxidation. To test its effects on E. faecalis, the bacteria were cultured anaerobically using the Hungate tube method, simulating human gut conditions, and then exposed to varying concentrations of potassium sorbate close to the FDA consumption recommendations. Growth curves were generated using turbidity via spectrophotometric measurements, and a 43% decrease in growth was observed during the exponential growth phase, 4 hours post-inoculation (alpha= 0.05, P= 1.37 x 10-5). These results support the hypothesis that this preservative inhibits bacterial growth, and future experiments are aimed at testing its effects on other common species. The human microbiome has quickly fought its way to the spotlight of the scientific community for its implications on metabolism and immune response; however, the current amount of research investigating unintended consequences of exposure to preservatives on this microbiome is lacking. As our knowledge of these implications increases, regulatory agencies such as the FDA may need to adjust their recommendations of additives allowed in food products.
