Temperature control is critical for safe food handling. Most bacteria, including those that cause milk to go sour, grow best in warm temperatures, that is, those between 41°F (5°C) and 135°F (57.2°C). Pathogenic bacteria favor slightly warmer temperatures in the 70°F (20°C) to 125°F (50°C) range. Temperatures of 170°F (80°C) or hotter will kill most non-spore-forming bacteria and all pathogenic organisms. Although low temperatures (32°F / 0°C) will not kill bacteria, they will hamper or slow growth so food can be preserved through refrigeration or freezing.