Cross Contamination is the bane of every food-safety management system.  While food safety professionals concentrate on the process flow through a food system, sanitation personnel should also be mindful of conditions where pathogens may reach otherwise safely processed foods. Preventing the transfer of pathogens from one product to another is important in almost every type of food handling activity.  From the farm environment to the consumer’s refrigerator, the potential is there for cross contamination. The residues of raw materials can easily cross contaminate machinery, equipment, utensils and other production tools in industrial settings, farms, restaurants or homes – the kitchen cloth may be a primary means of spread in the home.  Microbes may find those residues ample for multiplication or the microbes may already be there sufficiently to cause a hazard. Hands, clothing, environmental surfaces such as walls, ceilings and floors may become contaminated and create ongoing reservoirs of the hazard in the environment. Storage and the food handling conditions themselves may also provide the means for raw or contaminated products to contaminate finished or safe products. Sanitation Standard Operating Procedures are a part of a firm’s Good Manufacturing Practices (GMP). Having such procedures means the organization has assigned specific cleaning duties to specific personnel trained in those operations. Clearly written standards for using chemicals must include instructions for dilution and concentration and application. Visual checks for cleanliness and checks of sanitation logs are an onsite method of monitoring compliance with cleaning requirements. Microbial and chemical tests verify cleanliness and help to validate visual monitoring methods. Tests also evaluate efficacy of cleaning regimens and standard-plating techniques can provide in 48 hours or less information about potential microbial contamination. “Real time” or immediate measurements with ATP instrumentation, colorimetric tests, protein or sugar swabs, and titration allow monitoring of the cleaning processes as it occurs. Poorly designed or maintained surfaces resist cleaning and are therefore more susceptible to contamination. Stainless steel surfaces of various grades are preferred in processing environments depending on the nature of production. Liquid products such as dairy or processed egg products may have very high-grade surfaces while produce or other agricultural products, such as peanuts, may not. Highly cleanable surfaces provide a benefit in reducing the threat of cross contamination; surfaces that resist cleaning are higher risk. Surfaces may allow transfer of contamination when they are pitted, rusted, broken or loose and poorly maintained. Facilities should evaluate the design of these surfaces and the design of the entire processing environment and provide for maintenance. The USFDA Food Code is specific about food contact surfaces, their design and configuration. The code is also specific about the use of sanitizers and the cleaning and sanitizing process. Compliance in these areas of the code is challenging. In a busy facility whether it be a restaurant, a processor or a manufacturing plant, production environments become quickly soiled. Daily cleaning will remove the residues before they have had time to encrust and harden. Food materials actually create weak ionic bonds with substrates; often requiring a solvent to remove material bonded to the surface. Surfactants are sufficient to remove loosely attached debris, greases, fats, and oils. Once surfaces are clean, sanitizing employs several methods including chemicals, UV light, electrolyzed water, heat and steam. Bio-films are the end result of poor cleaning practices. Bacteria protect themselves within the bio-film matrix resisting cleaners and sanitizers. Sometimes only physical effort will remove a biofilm, scrapers, sanders and torches are occasionally required. Maintaining a safe working environment is not negotiable, and lack of cleanliness is an obvious sign of a poor “food safety culture.”  Nevertheless, preventing cross contamination in a facility and reducing its occurrence takes a team of dedicated persons with good tools, adequate water and chemicals, knowledge about their use, and the skill to make the solutions work correctly. Management must oversee the sanitation program and assess its effectiveness. Even facilities with otherwise complete food safety systems often do a poor job training sanitation workers in the proper execution of their duties and sanitation crews are often the lowest paid workers. Since they “do not produce”, they are the first to go in any budget crisis. It is a true test of a food safety culture when the top priority of the plant is cleanliness. Being double-crossed by the microbes and failed food safety systems otherwise result.