The present invention provides starchy food products, especially cooked and fully hydrated potato compositions, including fully hydrated mashed potato compositions and fully hydrated cut potato compositions, which are stabilized against the development of toxins from pathogenic bacterial contaminants. The stabilized compositions are attained by the incorporation of nisin-containing dairy composition derived from a nisin-producing culture. The invention also relates to methods of stabilizing starchy food products, especially cooked and fully hydrated potato compositions, including fully hydrated mashed potato compositions and fully hydrated cut potato compositions, against the development of toxins, wherein the method comprises incorporating nisin-containing dairy composition derived from a nisin-producing culture to the starchy food product. Since these compositions are cooked and fully hydrated prior to packaging, the ultimate consumer only needs to briefly heat the starchy food product in, for example, a conventional or microwave oven prior to consumption.