Methods of sanitary-hygienic treatment
Cleaning and disinfection can be performed manually with simple tools, for example, brushes and rags (manual cleaning), although special equipment is needed to increase the areas of exposed surfaces that require cleaning and disinfection, for distributing detergents and / or providing sufficient mechanical energy. Chemicals can be used in the form of a dilute haze haze, foams or gels, and the supply of mechanical energy is provided by high and low pressure hydraulic nozzles or rigid brushes driven by water or electricity. These methods are well described, and below we will only consider their application in practice.
Using the purification method can be described schematically based on the cost of various energy sources and their ability to operate with low and high (dashed) contamination levels. For manual cleaning of small items can be put more mechanical energy directly where it is needed, and the use of tanks for soaking (or clean out the place of use) can be increased contact time and / or use more chemicals and heat.
The disassembled equipment and accessories can first be cleaned of dirt manually, and then washed and disinfected automatically in the hopper or tunnel washers. As with soaking in tanks, more chemical and thermal energy can be used to cope with most types of contaminants. Placement of sinks in high-risk areas for the production of refrigerated products should be carefully analyzed, since they can form a microorganism-containing aerosol, and it can cause air contamination of the product.
When hand washing / cleaning large surfaces use can be only a relatively low temperature and less chemical energy (due to the safety of the operator), and with an increase in the area requiring treatment, the method becomes uneconomical relatively time consuming and labor. Labor costs reach 75% of the costs of implementing the entire sanitation program, and for the majority of the food industry such an additional labor costs are too high. Manual cleaning is economical only in low pollution.
The main difference between the aerosol, foam and gel methods lies in their ability to provide the necessary contact time with the detergent and pollution of surface. For all these three methods can change the level of mechanical energy expended from the feeding aqueous detergent solution under high or low pressure, as for cleaning the exposed surfaces of the impact is minimal temperature.
Fig. 14.2. The use of different energy sources for various cleaning equipment
Spraying of the aerosol is carried out using small reservoirs with a hand pump, knapsack sprayers or low pressure washing machines. By spraying the aerosol, smooth vertical surfaces are only wetted, and therefore small amounts of rapidly flushing detergent can be used, providing a contact time of 5 min or less. As this method produces aerosols which, if inhaled, can be dangerous, only weak chemicals should be used, and therefore aerosol spraying is used only for a small degree of contamination (this method is the most common method for applying disinfectants to already cleaned surfaces).
Foams can be formed and applied by capturing air in high pressure equipment or by supplying compressed air to a low pressure system. The principle of the action of the foam is to form bubbles above the surface requiring cleaning, which then bursts and rinses the surface with the detergent contained in the bubble-forming film. In the formation of foam, it is essential that bubbles burst at an appropriate rate: if the speed is too high, the contact time will be minimal, and if the speed is too low, the surface will not be wetted by a fresh detergent.
Gels - a thixotropic chemicals, liquid at high and low levels, which become thick and gelatinous when concentrations of about 5-10%. Gels physically adhere to the surface and can easily be applied with a high and low pressure systems or special portable device with an electric pump.
Foams and gels have a greater viscosity than aerosols, and thus allow the use of more concentrated detergents. They can stay on vertical surfaces much longer (foams - 10-15 minutes, gels - from 15 min to 1 h and more). Foams and gels are capable of cleaning higher levels of contaminants than aerosols, although in some cases flushing surfaces may require more water (especially in the case of foam). Foams and gels due to their properties have been recognized by the staff, since it is better to apply chemicals and it is easier to identify the missed areas.
The systems of aerosol formation ("fogging") in the production of refrigerated products are traditionally used to create disinfecting fogs, since they reduce the content of microorganisms in the air and allow them to affect hard-to-reach surfaces in the upper parts of the premises. The effectiveness of treatment with a similar aerosol was recently studied in the UK. When using the appropriate disinfectant, the method is effective to reduce the number of microorganisms in the air in 100-1000 times for 30-60 min. The treatment with such a "fog" is most effective when using special fogging nozzles working on compressed air and forming particles of size 10-20 μm. For disinfection of surfaces, this method is effective in the event that the surface can be applied with sufficient chemical means. In Fig. 14,3 shows the logarithm of the decrease in the number of microorganisms achieved on horizontal, vertical and lower surfaces located in the test room at five levels - from the upper near the ceiling (276 cm) to the lower one Surfaces are much longer (foam - 10-15 minutes gels - on 15 1 minutes to hours or more). Foams and gels can be cleaned higher levels of contaminants than aerosols, although in some cases, flushing of the surfaces may require more water (particularly in case of foams). Foams and gels due to their properties were recognized by the staff as the best applied chemicals and easier to identify missed areas.
From the above it follows that stronger disinfection on surfaces arranged near the floor and the bottom surfaces is minimal near the ceiling. To reduce the risk by breathing to the disinfectant fog could settle before returning to the operators in the production area is required 45-60 minutes after spray treatment.
Disinfectants are removed from the surfaces using low-pressure hoses with a high flow rate, operating at water pressure in the water pipe or using pressure washers that operate at high pressure and at low flow rates. Pressure washing systems usually work at a pressure of 25-degree nozzle 25-100 bar. Mobile or wall installations, as well as centralized circular pipelines, can be used. The nozzles, which provide a strong mechanical effect, can be used to clean a wide range of equipment and surfaces, as well as for mixing chemicals. They allow water to penetrate into the smallest surface irregularities.
Mechanical brushes are traditional floor brushes, automatic installations for cleaning / drying the floor, hydraulic accessories for high pressure systems and electric brushes of small diameter that can be used for cleaning floors, walls and other surfaces. When using these methods, the contact time is usually limited (although it can be increased), but the combination of detergent action and the supply of a large amount of mechanical energy makes it possible to remove most kinds of contaminants. The main limiting factor here is that the product processing zones have traditionally been designed without regard to their purpose, although this can be corrected in new and reconstructed zones.
Equipment for sanitation should be made of smooth, non-porous, easy-washing materials such as stainless steel or plastic. Soft (low-carbon) steel or other materials susceptible to corrosion can be used, but they must be appropriately painted or coated, and the use of wood is unacceptable. The frame must be made of tubular materials or have a box section; It must be closed on both sides and well connected - for example, the seams should be polished and sanded, and metal-metal connections are inadmissible. Care should be taken to avoid cracks and protuberances in which dirt can accumulate, threaded connections must be closed or blind nuts must be applied. Storage tanks for chemicals or regenerated liquids should be self-draining, have rounded corners and are easy to clean. Covers around brush heads and rotating brush heads for easy cleaning should be easily removable. Brushes should be with bristles made of painted waterproof material (for example, nylon reinforced in the head of the brush so that there are no places to delay contamination). Brushes with a head cast in the form of a single block can also be used.
Cleaning equipment can become infected with species Listeria And other pathogenic microorganisms, and therefore its use can move contaminants from one zone to another. In this connection, cleaning equipment in the high-risk zone should only be used within this zone, and after use it must be thoroughly cleaned and (if necessary) disinfected and dried. The ability of the purification equipment to disseminate microbiological contamination in the form of aerosols is described in , where it is shown that when all the tested systems were cleaned, the test surfaces contaminated with biofilms deposited on them formed an aerosol containing viable microorganisms.
The degree of surface contamination was divided into ranges - from full coverage to a minimally dangerous level (if the fraction of drops containing viable microorganisms, the maximum height and the distance covered by this level of contamination correspond to the data given in Table 14.4). If we assume the average height of the surface coming into contact with the food product equal to 1 m, the results show that up to this height, both in the high-pressure and low-flow (HDPE) method and in the low-pressure and high-flow method (NDBC ) Creates a significant amount of aerosol, and therefore they should not be used during production. For cleaning after the appearance of contamination, other methods are acceptable, however, since the probability of contamination of the product is low, but when using brushes and floor dryers (convenient that cleaning liquid is removed from the floor), if the product is stored on racks close to the floor, . Once production is completed, the VDNR and NDIR methods can be used without risk, but disinfection of surfaces coming into contact with food should be the last operation performed,
Table 14.4. The maximum height of the spray and getting away
for a number of treatment methods
|cleaning method||Height, cm||Distance, cm|
|High pressure / low flow ejected aerosol||309||700|
|Low pressure / high flow||210||350|
|Set for cleaning and drying the floor||47||80|
|Manual cleaning brushes||24||75|
raking or using a vacuum, and so on. d. Where possible contamination of floors and walls must be collected and placed in suitable containers for waste, not washed down the drain with a hose.
4. Pre-rinsing. To remove loosely adherent contaminants small surface should be rinsed with cold water at low pressure. The hot water can be used for greasy dirt, but too high temperatures can coagulation protein.
5. Cleaning. To remove adhered contaminants using different detergents, the temperature and the supply of mechanical energy.
6. The intermediate rinsing. Contaminants separated using purification, and detergent residues must be removed from the surface by rinsing with cold water at low pressure.
7. Disinfection. To remove and / or reduce the viability of the remaining microorganisms to a level that is considered non-hazardous, chemical disinfectants (or sometimes warm) apply. In exceptional circumstances, and only when you remove the weak contamination may be appropriate mix stages 5-7 using chemicals with a detergent and bactericidal action (detergents, disinfectants).
8. Subsequent rinsing. The remaining disinfectant must be removed by washing with cold drinking water at a low pressure. Some disinfectant must remain on the surface prior to the next period of production, and therefore their composition is such that they are surface-active, did not give off-flavors and food were not toxic.
9. Steps between production cycles. In the period before the next production cycle to prevent the growth of microorganisms different actions can be taken on wetted surfaces, including the removal of excess water and / or drying equipment. There is another option: the removal of the product from the premises and staff followed by treatment with an appropriate disinfectant spray facilities.
10Periodic processing. To achieve an acceptable level of cleanliness of certain equipment or periodic treatment zones are used, which increases the degree of purification. Such treatment includes weekly acidic cleaning, disassembly of equipment at the end of the week, cleaning and disinfection of cooling and sanitary-hygienic treatment of surfaces, fixtures and equipment at a height above two meters.
In order to ensure the fulfillment of tasks and regular products in the processing area cleaning programs should be set a clear sequence of sanitary measures. In particular, the order of sanitary operations, determines the sequence in which the parts in contact with the surface of the product of the equipment and the working environment (walls, floors, drains, etc...) Is sanitized - so that after the disinfecting of these surfaces, they're not polluted .
On the basis of real-life examples have shown that to combat the breeding of undesirable microorganisms can recommend the following sequence of operations sanitizing production zone chilled products (this sequence must be implemented so that all surrounding surfaces and equipment in the area were cleaned at the same time - cleaned and disinfected one line, and then move to another and can not perform the sequence of operations again as this only applies impurities):
♦ cleaning of production equipment from major pollution;
♦ cleaning of industrial premises surfaces of coarse dirt;
♦ washing of industrial premise surfaces (walls usually to a height of not less than 2 m);
♦ washing equipment and solutions in the sewer drain;
♦ cleaning the surfaces (usually, first drains, walls, floors and then);
♦ washing of industrial premise surfaces;
♦ cleaning equipment;
♦ washing equipment;
♦ disinfection of equipment (if necessary washing);
♦ spray treatment (if necessary).