Preparation and storage of frozen sweet corn Preparation : For best results always cook from frozen. Please ensure food is cooked until piping hot. For food safety and best quality, cook to 90 °C. Simmer for 4-5 minutes or steam for 9 - 10 minutes. Drain well before serving. Microwave for 3 - 4 minutes. These instructions are guidelines only. Serve with salt, butter, pepper or any other seasonings to taste. Enjoy. Storage : Keep frozen at -18°C or cooler. Once sweet corn has thawed, do not refreeze. For best before and date, see front of pack.