Microbial food contact surfaces

Sanitization is a cleaning procedure that reduces microbial contaminants on certain surfaces to safe or relatively safe levels, as defined by the EPA or pubHc health authorities. The article is usually cleaned with hot water and various germicidal detergents. Sanitization can be safe for a product in contact with intact skin or for food utensils, but it is not considered safe for articles to be inserted in the human body. Effective sanitization is a requirement in the processing of reusable medical suppHes before packaging and sterilization. It is also a requirement in the maintenance of utensils and containers used for food preparation. 

An alternative packaging is the combination of food-packaging materials with antimicrobial substances to control microbial surface contamination of foods. For both migrating and nonmigrating antimicrobial materials, intensive contact between the food product and packaging material is required and therefore potential food applications include especially vacuum or skin-packaged products (Vermeiren and others 2002). 

Humans may be programmed to be more sensitive to natural food contaminants. For instance, (-)geosmin (rrans-l,10-dimethyl-rran5-9-decalol) occurs in earth, natural surface water, and in foods in contact with soil or water, such as beets, clams, or fish. Geosmin is a microbial, fungal, or algal metabolite. It is a water pollutant and off-flavor compound. The naturally occurring (-)enantiomer has a threshold 11 times lower than the (-I-) enantiomer (Polak and Provasi, 1992). 

Masonry products have been widely used in the construction industry and include building materials such as cementious materials, concrete, brick, tile, stone, grout, and like substances. Driveways, garage flooring, concrete block, brick fronts, fireplaces, fireplace hearths, as well as tiled floor, wall and counter top surfaces are exemplary applications. Masonry surfaces are porous and if left unprotected can deteriorate from exposure to water and they can become discolored. For example, water penetration can cause spalling or lead to discoloration via microbial growth. Tiles and grouts employed in homes come in contact with various foods and liquids, e.g., fruit juice, coffee, oils, ketchup, mustard, etc. that can cause discoloration. 

An alternative to release of antimicrobial agents could be the use of a surface that is inherently antimicrobial. Such a system could be applicable to liquid foods (especially if agitated) and those with intimate contact with the package surface. One such system is available in Japan (Louis, 1990 Hirata, 1992) and consists of a plastic film impregnated with silver-bonded zeolite particles. As the microorganisms contact the zeolite, they take up the silver, which kills them. A 1% silver zeolite in polyethylene has been evaluated in a model system by Hirata (1992) who found that the microbial count on the surface could be reduced from up to 10 cells/ml to less than 10 cells/ml in 24 hours. This system appears to have considerable promise. 

---