Determining the efficacy of glycolipids to control Listeria monocytogenes in Queso Fresco

Obj 1. Determine the efficacy of glycolipids to control L. monocytogenes in whole milk. Obj 2. Determine the efficacy of glycolipids as surface treatments to control L. monocytogenes as surface contaminants on finished product prior to packaging. Abstract: Environmental Listeria monocytogenes contamination continues to pose a threat to cheese safety irrespective of prior lethality treatments. This is of particular concern for high-risk cheeses (pH >5.6; moisture >50%; no starter culture; i.e. Queso Fresco) that have been shown to support L. monocytogenes growth to high levels. With that, and in response to new food safety regulations of the Food Safety Modernization Act, there is a critical need for actionable, science-based interventions to mitigate L. monocytogenes risk. In response to emerging consumer demand for safe yet minimally processed, "clean label" foods, the development of more natural control measures is most desirable. Glycolipids are natural products with demonstrated antimicrobial effects against a broad range of microorganisms. AM1 is a novel (patent pending) glycolipid product with activity over a broad pH range (pH 2.5-7) (AM-1, IMO Natural Solutions). It is a stable, off-white, tasteless, odorless, highly fat and water soluble powder that is readily incorporated in foods and beverages without affecting organoleptic properties. AM1 is derived from the fermentation of glucose by an edible mushroom and extracted by food grade precipitation and washing for clean labeling. The safety of AM-1 has also been demonstrated through multiple in vitro and in vivo studies. With demonstrated antimicrobial efficacy against Listeria at relatively low inhibitory concentrations in foods (250-500ppm), the proposed work will determine the efficacy of AM-1 and two commercially available products, rhamnolipids and 1',4"-Sophorolactone 6',6"-diacetate, to control L. monocytogenes in milk and as surface contaminants on Queso Fresco.