With a steadily growing knowledge of food-borne bacteria and how it functions, the USDA is now upping the ante on food producers when it comes to floors, drains and methods of sterilization. A good example of the new standards is found in the July, 2011 paper Milk for Manufacturing Purposes and its Production and Processing - Recommended Requirements:
"The floors of all rooms in which milk or dairy products are processed, manufactured, packaged, or stored or in which utensils are washed shall be constructed of tile properly laid with impervious joint material, concrete, or other equally impervious material. The floors shall be smooth, kept in good repair, graded so that there will be no pools of standing water or milk products after flushing, and all openings to the drains shall be equipped with traps properly constructed and kept in good repair."
It's a case of USDA on one side, OSHA on the other, and a whole lot of headaches and money spent in between. You've got to strike just the right balance between keeping bacteria-hiding crevices to a minimum and not creating a skating rink for workers. The fewer flaws in the surface, the less likely you are to build colonies of nasties like E. coli, salmonella, and the biggest baddie of them all, L. monocytogenes. But a floor which perfectly shrugs off micro-organisms is tough to safely work on.
For almost a hundred years, dairy brick (vertical fiber red shale brick) has been the go-to favorite for any food industry floor, followed closely by acid brick, which has been carefully fired for additional corrosion resistence. Tough, attractive, adaptable and time-tested, these floors are often what industry producers wish they could install when they settle on epoxy to better fit their budget.
Standard dairy or even acid brick floors have their downside, however. Even when correctly bedded and grouted, it's gradually become apparent they can never be cleaned thoroughly enough for the USDA's ever-more-exacting standards. Advanced cleaning methods containing powerful staying-power chemicals like sodium hypochlorite quickly begin to corrode the tiles and chip away at the grout, making them even less sanitary. The process of making the bricks non-slip creates small crevices and pores where liquid and septic bacteria take up permanent residence. Dairy brick isn't a good choice if inspectors are looking for a "smooth" floor "kept in good repair" and the corroded/open pore issue means bacteria transfer rate can become a serious problem. Some of the more spectacular recent food poisoning outbreaks have been caused by hidden bacteria on the floor becoming airborne during cleaning or construction and landing on equipment that was already clean and supposedly sanitary.
One of our favorite alternatives to standard dairy or acid brick is a product called VERSI-LINE (formerly Blome) Vitrified Ceramic Tiling Systems (VTS). It has a few unique properties that make it really stand out in a market presenting a bewildering array of possible replacement options. Made by the Denmark-based company Hempel, these tiles are made from a highly non-porous type of clay only found in certain regions of Italy. While even the best acid or dairy brick typically has an absorption rate of just under 5%, VTS comes in around 0.5%, giving it a fantastic hygiene standard when properly cleaned. (As always, proper cleaning is the real first line of defense...as long as your floors aren't sabotaging your efforts!)
Available as both floor and wall tiles in a variety of colors, VTS offers a similar classic appearance to dairy brick while actually being quicker and easier to install. It's unusually tight jointing process allows it to be laid without spacers and smoothly sloped toward drains; and as a bonus, it's small grout lines (about 2 mm wide) add to it's corrosion-and-microbe-resistant properties.
As far as slip hazards go, VTS is easy on the HACCP plan. The tiles come with several slip-resistant pounded surface (rather than cut or cinder-embedded) choices that leave them non-porous but safe to walk on while wet with just standard tread shoes.
Because it holds up so well to the high-stakes cleaning situation of food production floors, the cost of installing a Vitrified Ceramic System floor sees a pretty respectable return on investment when the lifespan of the floor stretches far beyond the average 10 years until replacement. VTS initially comes with a 5-year warranty but is ultimately designed to last for a whopping 20 - 30 years.
A quick average-lifespan comparison of several types of food production floor options:
Epoxy (1/4" troweled): 8 years
Urethane Concrete: 10 years
Acid/Dairy Brick: 20 years
Vitrified Tile: 30 years
If you're looking to install a floor in your facility that will help you beat the 39% odds your next floor swabs will come back contaminated, VTS might just be the best route to go.