Chapter 5 Food Contact Surfaces

CHAPTER 5: FOOD CONTACT SURFACES Definition Food contact surfaces are defined as “all surfaces that may come into contact with food products during production, processing, and packaging.” Or surfaces that contact human food and those surfaces from which drainage onto the food or onto surfaces that contact the food ordinarily occur during the normal course of operations.” Included in this definition are utensils, as well as equipment surfaces. Cleaning and sanitizing food contact surfaces is one of the most important steps to prevent foodborne illness. Food residues on food contact surfaces and equipment can provide an ideal environment for the growth of disease-causing bacteria. A food product contact surface is defined as a surface in "direct contact with food residue, or where food residue can drip, drain, diffuse, or be drawn" (FDA, 2004b). These surfaces can be furnished from a range of food-safe and/or food-grade materials, such as stainless steel, plastic, wood, rubber, glass, or ceramics. Food Contact Material (FCM): Any material intended to come into contact with food, that is already in contact with food, or that can reasonably be expected to come into contact with food, is considered Materials and articles which are in contact with water intended for human consumption from the point at which they enter a food business premises, are also considered to be food contact materials. They also include materials used in processing equipment, such as coffee makers, blenders or production machinery as well as containers used for transport. Although these materials may vary, all must be strong enough to stand up to frequent cleanings with harsh, acidic cleansers. The food contact surface cannot buckle under the strain of various elements, particularly high temperatures. Typically, food contact surfaces require ultra-smooth surface finishes that are devoid of pores or crevices that might attract fallen food particles, lending to bacterial growth. Criteria used to deem a food surfaces contact safe In terms of sanitary design, all food contact surfaces should be: smooth; impervious; free of cracks and crevices; nonporous; nonabsorbent; non-contaminating; nonreactive; corrosion resistant; durable and maintenance free; nontoxic; and Cleanable. If the surface is coated with metal alloy or non-metal (e.g. ceramics, plastic, rubber) in any way, the final surface must meet the above requirements. 3A Standards require that such coatings maintain corrosion resistance, and be free of surface delamination, pitting, flaking, chipping, blistering, and distortion under conditions of intended use. Similarly, if any other modification or process is used in fabrication (e.g., welded, bonded, or soldered) it should be done using appropriate materials and in a manner that ensures the final surface meets the sanitary design criteria. Common Food Contact Surface Materials 1. stainless steel 2. Plastic material 3. Wood 4. Rubber 5. Ceramics 6. Glass. 7. Cardboard 8. Silicone 9. Paper N/B Often, a combination of materials is used. A fruit juice carton may contain layers of plastic, aluminum, paper & ink. Outer garments, aprons & gloves are also considered food contact surfaces.  Frequently wash them  When not in use should be stored in clean, dry areas, separate from soiled clothing.  Company policy should be established for buying, cleaning, storing & replacement of clothing and gloves  Ensure they’re not exposed to dust & other contaminants Examples of food contact surfaces: • Knives, spoons, grater, scoops, spatulas. • Pots, pans, mixing bowls, colanders, cutting boards. • Prep tables, produce sinks, scales. • Thermometers • Tilt skillets, food processors, mixers, kettles, slicers, fruit quartier, The materials must be manufactured in compliance with safety regulations, including good manufacturing practices. Any potential transfer to foods should not:  Raise safety concerns  Change the composition of the food in an unacceptable way  Have adverse effects on the taste and/or odor of foods. Risk posed by materials is assessed by measuring:  Potential toxicity  Consumer exposure to substances.  Rate of migration of substances from the material into food All food contact materials (including surfaces) must be covered by at least one of the following: A regulation listed in Title 21 Code of Federal Regulations Meeting the criteria for GRAS (Generally Recognized as Safe) status (including but not limited to a GRAS regulation or GRAS notice) A prior sanction letter A Threshold of Regulation (TOR) exemption request An effective Food Contact Substance Notification (FCN) Design Requirements for Food Contact Surfaces Food contact surfaces should be constructed & designed so they can easily cleaned and sanitized Any seams & joints should be smoothly bonded Equipment should be designed to avoid sharp angles or structures that hinder proper cleaning & sanitation Surfaces should drain & not entrap soils Conveyor belts should be made of non-absorbent & corrosion-resistant materials that are easy to clean A variety of materials are used in the construction and fabrication for different applications in food equipment. These materials vary in their properties with regard to workability, compatibility, and sanitary design features. Depending upon the application, various metals as well as non-metals (e.g., plastics, rubber) are used. Some materials are not recommended and should be avoided. Metals Stainless steel is the preferred general use metal for food contact surfaces because of its corrosion resistance and durability in most food applications. However, not all stainless steel is equal. In general, the properties of the stainless steel alloy are related to its relative composition with regard to chromium and nickel level. Corrosion resistance varies with chromium level, and structural strength varies with nickel level. The relative levels of these components are often given as a ratio. For example, the American Iron and Steel Institute (AISI) 300 Series Stainless Steel, commonly recommended for food contact surfaces is also termed 18/8 indicating that it is 18% Cr and 8% Ni. 3A Sanitary Standards require 316 (or 18/10) stainless steel for most surfaces. They allow the use of 304 stainless steel only for utility usage (e.g. pipes), and restrict the use of 303 stainless steel. 3A Standards also provide specifications regarding alloys and other coatings used in fabrication. The properties of stainless steel can change with continued use, especially under conditions where the chromium oxide layer is altered (e.g. incompatible cleaners, abrasive cleaners, abrasive cleaning pads, or chlorine and related sanitizers). Therefore, it is recommended that surfaces be passivated (using nitric acid or other strong oxidizing agents) initially and on a regular frequency thereafter, to maintain a passive (non-reactive) oxide film on the surface. Passivation of stainless steel food contact surfaces is recommended after any surface repair, polishing, or working. Titanium has excellent durability and corrosion resistance (especially in an acidic environment). However, its use is limited by high cost. Titanium is used in stainless steel alloys for food equipment used in the processing of food products with high acid and/or salt content (e.g., citrus juice, tomato products). Platinum, another excellent corrosion resistant material, would also be highly desirable, but, obviously, the cost of this rare material would prohibit its use. Gold has been approved as a food contact surface in certain 3-A Sanitary Standards. In some cases, gold is used for soldering optical sensors (e.g., fiber optics) into stainless steel fittings. Gold is desirable in these applications for its resistance to abrasion and compatibility with glass. Other metals are limited by application as follows: Copper is primarily used for equipment used in the brewing industry, with some use for cheese vats in Swiss cheese manufacture, due to tradition. Care should be used with copper equipment when processing acid products, as copper residues can leach into the product. Aluminum is used in certain parts and components where lighter weight is desired. However, aluminum has poor corrosion resistance and can become pitted and cracked with continued use. Care should taken when cleaning and sanitizing aluminum components as oxidizing chemicals can accelerate the pitting of the metal. In most food contact applications, aluminum must be coated with an acceptable material. Plastic coatings such as polytetrafluorethylene (PTFE or Teflon®)are common. Carbonized metal and cast iron are only used for frying and cooking surfaces, and similar applications in food service. Galvanized iron should be avoided as a food contact surface because it is highly reactive with acids. Non-Metals A variety of non-metal materials are used as food contact surfaces in specific applications of food equipment (e.g., probes, gaskets, membranes). These materials should meet the same sanitary design and cleanability requirements as metals when used in these applications as described in 3 A Sanitary Standards and other standards. Non-metal surfaces, in general, lack the corrosion resistance and durability of metal surfaces, therefore, maintenance programs should include frequent examination for wear and deterioration under continued use, and replacement as appropriate. Non-metal materials used in food contact surfaces include: Plastics, rubber, and rubber-like materials that should be food grade and should meet the requirements designated under 3A Sanitary Standards (18-03 and 20-20). Multi-use plastics, rubber, and rubber-like materials may also be considered as indirect food additives under FDA regulations. Ceramics are used primarily in membrane filtration systems. They may also be used in other limited applications if wear resistance is necessary. Glass may be used as a food contact surface. These applications are limited due to the potential for breakage. Specially formulated glass materials such as Pyrex® have proven successful. When glass is used, it must be durable, break resistant or heat resistant glass. Some applications where glass is used are light and sight openings into vessels and in very limited glass piping applications. Paper has been used over the years as a gasket material in piping systems designed for daily disassembly. Paper is considered a single use material. Wood, which is highly porous and difficult to clean, should be avoided as a food contact surface. Wood is restricted in food service applications by most regulatory agencies, with the exception of hardwood cutting boards and tight grain butcher blocks. Surface Texture and/or Finish If any surface is ground, polished, or textured in any way, it must be done so the final surface is smooth, durable, free of cracks and crevices, and meets the other sanitary design requirements described above. 3A Sanitary Standards require that ground or polished stainless steel surfaces meet a No. 4 ground surface, and unpolished surfaces meet a No. 2B or mill finish. The 3-A Sanitary Standards development group has recently adopted an industry recognized method for determining an acceptable food contact surface termed roughness average or Ra value. The Ra is determined using a sensitive instrument (termed a profilometer) which employs a diamond tipped stylus to measure peaks and valleys in a relatively smooth surface. Hygienic standards of food contact surfaces The seven basic principles for hygienic design agreed by the Working Party appointed by the Joint Technical Committee of the Food Manufacturers Federation (FMF) and the Food Machinery Association (FMA) included in their publication Hygienic Design of Food Plant (1967) are a useful starting point in any discussion on hygiene. The principles are: I. All surfaces in contact with food must be inert to the food under the conditions of use and must not migrate to or be absorbed by the food. 2. All surfaces in contact with food must be smooth and non-porous so that tiny particles of food, bacteria, or insect eggs are not caught in microscopic surface crevices and become difficult to dislodge, thus becoming a potential source of contamination. 3. All surfaces in contact with the food must be visible for inspection, or the equipment must be readily disassembled for inspection, or it must be demonstrated that routine cleaning procedures eliminate possibility of contamination from bacteria or insects. 4. All surfaces in contact with food must be readily accessible for manual cleaning, or if not readily accessible, then readily disassembled for manual cleaning, or if clean-in-place techniques are used, it must be demonstrated that the results achieved without disassembly are the equivalent of those obtained with disassembly and manual cleaning. 5. All interior surfaces in contact with food must be so arranged that the equipment is self emptying or self draining. 6. Equipment must be so designed as to protect the contents from external contamination. 7. The exterior or non-product contact surfaces should be arranged to prevent harboring of soils, bacteria or pests in and on the equipment itself as well as in its contact with other equipment, floors, walls or hanging supports. Clean and sanitary food contact surfaces are fundamental to the control of pathogenic microorganisms. Contamination of food through direct or indirect contact with unsanitized surfaces potentially compromises the safety of the product. Cleaning and sanitizing involves:  Dry clean: Simply using a broom or brush to sweep up food particles & soil from surfaces.  Pre-rinse (brief): Uses water to remove particles missed by the dry-cleaning & prepares (wets) the surfaces to detergent application.  Detergent application (may include scrubbing): Assist with particle removal and reduces cleaning time and water consumption. Many household cleaners and those intended for extensive hand contact are quite mild and surfaces. safe for use on painted and corrodible  Disruption (scrubbing): Physical disruption is often required to assist in dirt removal. Cleaning aids must be carefully selected. They include: brushes, pads and pressure spray depending on the application.  Post-rinsing: Water is used to remove detergent and loosen soil from food contact surfaces. Process prepares the cleaned surfaces for sanitizing. All the detergents must be removed in order for the sanitizing agent to be effective.  Sanitizer application: After FCMs have been cleaned, they must be sanitized to eliminate or at least suppress potentially harmful bacteria. Types of Chemical Sanitizers:  Chlorine sanitizers’ e.g. household bleach: effective against many types of bacteria and mold. Work well at cool temperatures & tolerate hard water. Also inexpensive.  Ultra-violet light  Hot water/steam