Hygienic equipment design-refers to the engineering design of facilities and equipment for food handling, processing, and storage that can create a hygienic processing environment to continuously, reliably and economically produce pure, pollution-free, and high-quality products.

In the food industry, Woan has summarized and combed its production practices for many years, and obtained the following experience:

(a) All factory equipment and appliances should:
• Can be fully cleaned
• Exclude any lubricating oil, fuel, metal fragments, contaminated water or any other pollutants from entering
• Installation and maintenance must be for easy cleaning
• Prevent rust when in contact with food
• Made of non-toxic materials, designed to withstand the environment in which it is intended to be used
(b) The surface gaps in food contact must be connected and maintained smoothly to minimize the accumulation of food particles, dust and organic objects, and minimize the possibility of microbial growth.
(c) The equipment structure in the food production and processing area but not in direct contact with the food must also have conditions that can be kept clean

Woan has many years of experience in the design of sanitary equipment in the meat industry, and it also provides clear and direct guidance for food production. No matter what type of food you are processing and providing, the basic principles of equipment can be considered "hygienic" are as follows:

1. Can be cleaned to microbial level
2. Use compatible materials
3. It can be inspected, maintained, cleaned and disinfected without special tools
4. Areas where no product or liquid can accumulate
5. All hollow areas are sealed
6. No slots
7. Can be operated in a hygienic manner
8. Hygienic compatibility with other factory systems
9. Protocols for cleaning and disinfection can be verified
 


Solve the ten major elements of sanitary equipment design


 1. Does the surface of the food contact material meet the CFDA standards of the State Food and Drug Administration?

Does the surface of the material contacted by the food comply with CFDA standards? According to the requirements of CFDA, there are 5 rules to be considered. Simply put, the surface that food comes into contact with must not react with the product, will not contaminate the product, will not rust, will not absorb any kind of liquid, and most importantly, be able to clean. Only in this way can it be ensured that no biofilms will be produced, there will be no hiding places for microorganisms, no residues containing allergens, and no other chemical pollutants will be left behind.

The importance of these 5 rules can be seen in Figure 1. Under high magnification, we can see that the stainless steel surface on the left is the surface of the stainless steel before the equipment has not been activated. Please pay attention to its cracks and gaps. On the right is the picture after being used in a food factory for a period of time. We can see microorganisms enter these crevices and settle here. If these microorganisms survive long enough in the equipment, they will form a biofilm, which is very difficult to remove. Therefore, incorrect design and manufacture of equipment can carry a lot of bacteria.

Figure 2a shows a hole in a stainless steel radiator. Figure 2b shows how bacteria spread throughout the pores if the necessary measures are not taken to clean at the microbial level. Obviously, these microorganisms will continue to grow and reach the side of disinfection or pasteurization without too long. Of course, the sanitary design of equipment is not just to help prevent microorganisms, a food hazard. Take a look at your factory. Are all the equipment unpainted? Remember, in the food production area, no surface in contact with food can decontaminate the product. The paint is not good because it may peel off and enter your product, and the equipment without a protective layer may rust. (image 3). Detergent, hot water scouring, and even shelf vibration can cause paint to fall off. Obviously, if there are painted parts in the existing equipment, they must be replaced to avoid this inevitable problem.

2. Are all the welds in the food contact area hygienic welds? Are there no overlapping welds in all production areas?
Of course, improper welds in processing equipment are the most common and most likely obstacle to obtaining good sanitary results.
Two welds on the stainless steel plate. On the left is the joint welding seam of the board butt joint. This is the welding method we want, and there is no overlap. But the welding method here forms a bend. Bending will cause cracking, leaving dust, microorganisms and unwanted residues below the overlap point, which is difficult to remove with general disinfection methods. Even though the left plate is welded very well and uniformly, because it is not flat enough, it has not been polished, so microorganisms will still remain. For a good welding, the seam must be smooth and polished until the texture of the two adjacent pieces is the same. The welding on the right is very unsanitary. More cracks and depressions will leave more biological and chemical residues. Figure 5, Figure 6 and Figure 7 show how sanitary welding is. In Figure 5, we can see the side where the plate is welded. The weld has no protruding ridges, but there are depressions where microorganisms and dust may hide. The weld in Figure 6 has a back ridge, which has not been leveled and polished, and there are still food safety issues. The last figure 7 is the sanitary welding that has been smoothed and polished.

Does the horizontal food contact surface/contact area have recessed fasteners?

If there is a recess in the head of a hexagonal screw, a Phillips screw or other fasteners, then sanitation is not enough. These depressions may cause solid traps, metal-metal contact and dead ends. If there is a depression in the water surface, water vapor and other dust will accumulate and become nutrients for the growth of bacteria. To avoid this situation, all the fastening nuts must be under the surface that is in direct contact with the food. There is nothing on the front. The screws are fastened from the bottom and sealed with gaskets. Make sure that all nuts (nuts) are installed on the outside of the device so that if the screws are loose, they will fall on the floor. If the nut is installed inside, it may fall into your product, and since the screw is still in place, you will not find that the nut has been lost. The nut itself should also be polished stainless steel, with no exposed threads, and the threads are covered to eliminate slots that may be clinging to bacteria.

4. Does the equipment in the production and ancillary areas have side strips? Whether the angle of the side strip does not exceed 180 degrees
If you have a stainless steel table in your factory for placing products, feel under the table. Many times, you will feel something slimy in your hand because there is a side underneath that cannot be cleaned and disinfected, and it contains a lot of dust and debris (bad design in Figure 14, bottom). All equipment must be checked for such edge strips. The upper part of Figure 14 is a good design, and the middle picture is the best design. It has no structural place for dirt to hide and contain.

5. Are all equipment feet designed to make it difficult for water vapor and debris to hide? Is it easy to clean around them?
When the feet are directly fixed on the floor, it is almost impossible to clean them. Water vapor and dust will accumulate in the crevices. It is better to raise the equipment feet (Figure 15) to clean the equipment. Place a tapered tube under each foot and weld it together so that the screws that fix the foot to the floor can be covered, and this clean and sloping surface can be easily cleaned.

6. Is there any space (2-5 cm) around the control dials installed on the brackets, frames, and pillars for cleaning?
The control dials (in fact, including signs, pipes, equipment, etc.) must not be against the wall, otherwise you will not see the situation behind them and cannot be cleaned. In fact, cockroaches like to hide behind electronic devices. The control dial should be riveted or use a separate support. We recommend using a stand, which is 1.5 cm to 3 cm away from the wall, so that the control dial can be seen and cleaned. If riveting is used in a frozen area, there may be problems with mold growth. Figure 17 shows the installation of the bracket. The disinfectant can see the back and lower part of the dial for effective cleaning. This approach is not expensive and can be retrofitted in existing factories. Similarly, the top of the control box and other switch boxes should also be inclined to prevent water vapor from staying on the top. These boxes should not use piano hinges, otherwise there will be a lot of dust accumulation. A pointed hinge can be used instead, there are not too many surfaces to clean, or food-grade stainless steel props can be used.

7. Are all motors, bearings and drive components installed on supports that are easy to clean?
Motors are notoriously easy to adhere to dust. As shown in Figure 18, motors placed on a solid ground are very dusty. The motor in Figure 19 is placed on the guide rail so that the dust will fall to the ground and can be cleaned.

8. If any compressed gas is used in the product contact area, is there a pressure regulator in the pipeline, and is equipped with a coalescing filter and air filter (0.2 micron, 99.99% efficiency) or other pollution prevention equipment in the downstream?
If compressed air is used in the product contact area, there will be a big disinfection problem. The compressed air pipe itself will cause bacteria to grow. why? Although the compressed air is dried to a pressure dew point below the lowest room temperature to prevent the accumulation of water vapor in the air line, if there is no filter, water vapor will still be generated. Especially when the pipeline passes through the freezing area, then passes through a relatively warm area, and finally enters the freezing area. Condensate will form in the pipeline, which is the element needed for bacterial growth. If you need to use compressed air in areas that are in contact with the product, for example, if you need air to escape, please make sure that the compressed air that may be in direct contact with the product has been filtered by at least 0.3 micron HEPA or other filters at each point of use ( Figure 20).

9. Are the rollers or rollers on the conveyor belt solid instead of hollow?
The hollow drum with caps at both ends will have water vapor enter the inside. Logically speaking, if something can go in, it can come out naturally and contaminate the belt when it rolls. Many belt manufacturers have produced various innovative belts in accordance with hygiene requirements. For example, spiral type, reverse bending type, or others (Figure 22a-c). These are all open or double-slit connection designs, which make the cleanliness and air passage better. These open designs make it easier to clean the rollers and wash away dust or chemical residues. It is a picture of the dirt gathered in the hollow tube. Therefore, it can be seen that solid rollers or rollers are very important. The conveyor belt must also be hygienic design to ensure maximum cleanliness. Many belt manufacturers have produced various innovative belts in accordance with hygiene requirements. For example, spiral type, reverse bending type, or others. These are all open or double-slit connection designs, which make the cleanliness and air passage better. These open designs make it easier to clean the rollers and wash away dust or chemical residues.

10. Is there no "dead leg" larger than twice the diameter of the pipe in the pipeline system?
The situation shown may be fatal. Take a look at what happens in the "dead spot".
As shown in Figure 24, if you are going to clean from this direction, the blank T direction will be filled with cleaning materials. If even 5ml of slightly viscous and low acid product is mixed with Escherichia coli, after 24 hours, you will get 200 x 106 mL of Escherichia coli. When you wash out 1 mL of 200 x 106 mL E. coli per hour, and your production volume is 5-106 mL per hour, then the pollution amount is 200/5, which means there are 40 E. coli per mL of product. These bacteria stay in the "dead spots" and easily enter the product through the pipeline. Therefore, remove these "dead spots". If you really can’t get rid of the “dead corners”, at least make sure that their diameter is not more than twice the pipe diameter—not more than 1 pipe diameter is better—depending on the fluidity of your product. If your pipeline has an angle, it should be able to flow from any direction. At least make an elbow at the T-shaped intersection.
The design of sanitary equipment is a comprehensive and systematic work. The two articles in this issue cannot repeat all the points of view. In the later articles, we will continue to discuss related issues with users of Woan.

**Professional cleaning equipment provider, escort for regulated production and food safety.

More information, please contact local Wone service person or visit Wone website.

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