Cross Contamination
Your cutting board may be contaminating your veggies. How is that possible? Through cross-contamination! Cross-contamination occurs when microorganisms (bacteria, parasites, viruses)are transferred from a food where they occur naturally to one where they do not naturally occur. This is dangerous because unsuspected foods are not necessarily prepared in a manner to prevent the survival of microorganisms from other sources. Taking precautions to prevent cross- contamination will minimize the risk of foodborne illness in your facility and help ensure the food your customers receive is safe.

Food can become contaminated by microorganisms from many different sources during storage, preparation, and service. There are three (3) main routes through which cross-contamination can occur:

  • Food to food

  • Equipment to food

  • People to food
  • Food to food
    Food can become contaminated by microorganisms directly from other foods. This type of cross-contamination is especially dangerous if raw foods come into contact with cooked or ready-to-eat foods. Here are some examples of food to food cross-contamination:

    • In a refrigerator, meat drippings from raw meat stored on a top shelf might drip onto cooked vegetables placed on a lower shelf.

    • Raw chicken placed on a grill touching a steak that is being cooked.
    People to food
    People can also be a source of cross- contamination to foods. Some examples are:
    • Touching raw meats then handling vegetables or other ready-to-eat foods without washing hands between tasks.
    • Using a food soiled apron or towel to wipe your hands between handling different foods.
    • Failing to change gloves between handling different foods.
    Equipment to Food
    Contamination can also be passed from kitchen equipment and utensils to food. This type of contamination occurs because the equipment or utensils were not properly washed and sanitized between each use. Some examples are:
    • Using unclean equipment such as slicers, can openers and utensils to prepare food.
    • Using the same cutting boards, utensils, and/or work surfaces for both cooked and raw foods, such as with raw chicken then with vegetables.
    • Storing a cooked product, such as a sauce, in an unclean container that previously stored raw meat.
    Preventing cross-contamination
    Follow these steps to prevent cross- contamination and reduce hazards to food:
    1. Wash your hands after touching raw foods or items that contacted raw foods.
    2. Wash and sanitize all food contact surfaces:
      • Between use with different species of meat (beef to fish)
      • When switching from raw to ready-to-eat foods.
      • Every 4 hours during continuous use.
      • After final use of the day.
    3. When storing raw meats top-to-bottom always store the foods requiring higher cooking temperatures below other product (i.e., raw poultry below raw beef). See Guidelines for Final Cooking Temperatures.
    4. Store foods properly by keeping all foods covered and separating ready-to-eat foods from unwashed or raw foods.
    5. Prepare only one type of food at a time then wash and sanitize food contact surfaces before using them with a different food.
    6. Plan the order of raw food preparation such that foods requiring lower cooking temperatures are prepared first (i.e., cut vegetables, then beef, followed by chicken).
    7. Designate certain equipment for use with specific types of food only, such as using one slicer for cheeses and the other for meats.
    For further information
    For further information about food protection, please contact the Resource Management Environmental Health Division, (707) 784-6765.