TCS stands for Time/Temperature Control for Safety, and it refers to food items that require certain time and temperature controls to limit the growth of illness-causing bacteria. TCS foods are more likely than others to become unsafe to eat, and they have the highest potential for causing foodborne illness. A food item is determined to be a TCS food by considering five factors: pH, water activity, interaction of pH and water activity, heat treatment, and packaging. Examples of TCS foods include meat products, eggs, fish and shellfish, dairy, cooked vegetables, potato dishes, protein-rich plants, raw sprouts, cut leafy greens, cut garlic in oil, and sliced melons and tomatoes. Bacteria need food, moisture, and warmth to grow, and TCS foods have the nutrients and moisture bacteria need to grow. Add time and warmth to the mix, and these foods can become bacteria breeding grounds. To prevent dangerous growth, TCS foods are kept out of the temperature danger zone or moved through it quickly. Food temperatures are controlled with freezing, refrigeration, or holding. Food is refrigerated or frozen until it is prepared for service. If TCS foods are ready-to-eat, they can be safely consumed in a four-hour window. If they have not been temperature controlled, they should be discarded after four hours. Hot held and cold held foods can be served for four hours without temperature controls if they are discarded after the four-hour time limit.