Sergey Banadysev, Doctor of Agricultural Sciences, SGC DokaGene
A high production culture is a separate significant factor in the efficient storage of potatoes. The enterprise must have a strict schedule of work of different frequency to ensure constant cleanliness at the storage stage. It is recommended to obtain a certificate of good hygiene practice in the store. The audit conducted at the same time helps to identify problems with the fulfillment of essential requirements regarding the cleanliness and condition of the equipment and the storage as a whole. The audit also establishes the availability of documentation for the regulation of the most important types of work (tab. one).
Table 1. Criteria for assessing the level of hygiene of storage of potatoes
|1.||The store is cleaned and properly maintained. YES / NO 5/0 There is a corresponding written regulation.|
|2.||The storage is cleaned and disinfected before use. YES / NO 5/0 There is a corresponding written regulation.|
|3.||The store is sufficiently isolated or isolated from external pollution. YES / NO 10/0|
|4.||The area near the storage facility is cleaned and maintained in proper order. YES / NO 5/0 There is a corresponding written regulation.|
|5.||The floors in the store are always dry. YES / NO 5/0|
|6.||The product processing area is protected from the ingress of sewage or surface water by barriers or by sufficient distance. YES / NO 10/0|
|7.||The presence of a procedure for processing / disposing of non-standard products. YES / NO 15/0 There is a corresponding written regulation.|
|8.||The presence of a procedure for the treatment / disposal of waste and impurities. YES / NO 15/0 There is a corresponding written regulation.|
|9.||Packaging containers are stored in accordance with the rules and protected from contamination (birds, rodents, pests, etc.) YES / NO 10/0 There is a corresponding written regulation.|
|10.||Pallets, boxes, crates, etc. are clean, in good condition and do not introduce foreign material into the product. YES / NO 5/0 There is a corresponding written regulation.|
|11.||Product stored outside in trucks, bins, containers or on the floor in bulk is covered and protected from contamination. YES / NO 10/0 There is a corresponding written regulation.|
|12.||Non-food substances such as paints, lubricants, pesticides, etc. are not stored in the immediate vicinity of the product. YES / NO 10/0 There is a corresponding written regulation.|
|13.||The mechanical equipment used during storage is clean and prevents product contamination. YES / NO 5/0 There is a corresponding written regulation.|
|14.||Measures are taken to help exclude pests (insects, rodents) from the store YES / NO 10/0 There is documentation that guarantees this.|
|15.||Availability of a pest control program in the repository. YES / NO 10/0 There is supporting documentation.|
|16.||Interior walls, floors and ceilings are in good condition and free from dirt and cracks. YES / NO 5/0|
|17.||Drinking water is used to cool / humidify products. YES / NO 10/0 Supporting documentation is available.|
|18.||Availability of written storage regulations at the enterprise. YES / NO 10/0|
|19.||Securing the responsibility of specialists for storage. YES / NO 10/0|
|20.||Storage chambers are monitored for compliance with the established regime of temperature and humidity. YES / NO 10/0. There is a corresponding written regulation.|
|21.||Thermometers and psychrometers are checked for accuracy. YES / NO 5/0 Supporting documentation is available.|
|22.||There is condensation on the product, walls, ceiling. NO / YES, 15/0|
|23.||Condensation from refrigerators does not come into contact with the product. The refrigeration system is working properly. YES / NO 10/0|
|24.||Refrigeration equipment (condensers, fans, etc.) is maintained and cleaned on a scheduled basis. YES / NO 10/0 Is there any documentation that guarantees this?|
|25.||The processing of the product in the storage is carried out in compliance with the regime and damage control. YES / NO 15/0 There is a corresponding written regulation.|
|26.||Before starting the loading process, the vehicles are in good condition (clean, in good working order, no unpleasant odors). YES / NO 10/0 There is a corresponding written regulation.|
|27.||The company has written regulations for carriers and vehicles to maintain the specified temperature during transportation. The regulations indicate the temperature of the shipment and it is respected. YES / NO 10/0|
|28.||Vehicles are loaded to minimize product damage. YES / NO 5/0|
|29.||Staff areas (changing rooms, dining and recreation areas, etc.) are clean and located away from storage, transport and reception areas. YES / NO 10/0|
|30.||Records are kept indicating the source of the incoming product and the destination of the outgoing product, which allows you to uniquely identify and trace a specific batch. YES / NO 10/0 Is there any documentation that guarantees this?|
|31.||Total Assessment Points|
|32.||Maximum points possible = 265|
|33.||Match Ratio (31:32)|
The level of storage hygiene is assessed as excellent if the coefficient of conformity is higher than 0,9, good - above 0,8, satisfactory - above 0,7.
Regular cleaning, cleaning and disinfection can prevent the spread of many potato diseases.
Potato pathogens remain viable in storage for a very long time. The warehouse equipment and the storage room itself serve as reservoirs for harmful fungi, bacteria, insects, nematodes and weed seeds. They spread from tuber to tuber, from field to field on equipment, during storage, and cause problems if not eliminated, or at least minimized. So the causative agent of silver scab is able to survive for at least nine months on foam insulation and soil deposits and about three months in plywood and sheet metal. The causative agent of bacterial ring rot remains for up to three years on hard surfaces and up to seven years on wooden surfaces. Certain diseases, such as bacterial ring rot (caused by Clavibacter michigaense), can greatly complicate the work of seed potato growers, even if the manifestations of the disease are minor. The best method to minimize the spread of pathogens is through a rigorous sanitation program for equipment and storage facilities.
Most pests can be effectively eliminated simply by removing all soil and debris. Soil adhesion occurs on all field and tillage equipment and is not limited to specialized potato cultivation machines. Thus, the number one task for the agricultural producer is the complete removal of soil from the equipment. Cleaning can be done with pressurized water or steam equipment. Note that each of these methods can remove / damage the paint.
Field equipment should be cleared of soil at the previous field site or on non-agricultural land so that contaminated soil does not move to the new field.
Removing soil and dust containing millions of spores and microbes can also be done with an industrial vacuum cleaner.
The air ducts must be cleaned equally thoroughly. Just putting them outside in the sun is not enough. Disease-causing organisms in potatoes are able to survive on storage surfaces and equipment in rather harsh conditions - in the form of clumps or films of cells surrounded and protected by dried bacterial mucus, dried vegetable sap or other materials. Such formations are called biofilms and are difficult to dissolve and remove. Exposure to sunlight is a good final step in cleaning equipment or air ducts after they have been thoroughly rinsed and disinfected.
Disinfection is effective only on dry surfaces. On a still wet surface, the micropores of the material are filled with water, and the disinfectant solution cannot penetrate there due to surface tension. However, bacteria and microbes remain in the micropores. To get rid of them, it is necessary to take a break of several days between the pressure washer and the application of the disinfectant.
Some disinfectants can be applied by fumigation (these are usually aqueous solutions). Fumigation is very effective in healing closed rooms of any height and configuration (this result is often impossible to achieve with a sprayer, vacuum cleaner and car wash). But for the processing to be successful, a complete cleaning must also be performed first.
Disinfectants, recommended for use in potato storage (table 2), suppress all types of harmful organisms. They remove most bacteria, including those that cause quarantine diseases and wet rot. These active ingredients are effective against viruses and fungi, which is important for diseases that develop during storage, such as silver scab and fusarium. Disinfectants are very aggressive, have a low pH value, therefore, when working with them, you must use all protective measures (gloves, boots, glasses, masks, special clothing).
Table 2. Disinfectants for vegetable stores
|Commercial name||Active substance||Application rate / application method||Spectrum of activity|
|Eau de Javel corrodes metals||Sodium hypochlorite||10% (10l / 100l water), 2,5% (2,5l / 100l water)||Acts on fungi and bacteria|
|AB5 - corrosive in its pure form and non-aggressive to metal in a diluted form,||Formaldehyde (60 g / l) and glutaraldehyde (80 g / l)||1%, contact time 10 minutes; clean after rinsing, ideally with VMB (see below)||Against bacteria, fungi, viruses|
|VMB (cleaner and disinfectant) - corrosive in its pure form, non-corrosive on metal when diluted||Formaldehyde (24 g / l) and glutaraldehyde (32,5 g / l) + surfactant||2-5% (= 20-50 ml per liter of water); leave for 15 minutes, then rinse. No need to clean (thoroughly) the product|
|Waterfall - corrosion resistance to metal||Hydrogen peroxide (210g / l) and peracetic acid (55g / l)||0,2-2,5%, with a contact time of 5 to 15 minutes; without rinsing,||Bacteria, fungi, viruses, yeast|
|Desperox - corrosive and oxidizing, non-aggressive on metal in diluted form||Hydrogen peroxide (210g / l) and peroxyacetic acid (55g / l)||0,2-2,5% with contact time from 5 to 15 minutes with preliminary cleaning; without flushing||Bacteria, fungi, viruses, yeast|
|G-Extral Forte||Glutaraldehyde, 100 g / l||1-2% with a contact time of at least 20 minutes (+ soaking)||Bacteria, fungi, viruses and spores|
|Horthy-Desin - non-corrosive to metal in a diluted form||Glutaraldehyde (20g / l) and dimethylenedidesileammonium chloride (320g / l)||0,25% with a contact time of 15 minutes||Bacteria, fungi|
|Virocide - non-aggressive in dilution, non-aggressive on metal||4 different molecules: 2 quaternary ammonia (248,6 g / l) + glutaraldehyde (107,25 g / l) + isopropanol (146,25 g / l) + pinoil (20 g / l)||0,5% with a contact time of 15 minutes; rinsing after.||Bacteria, fungi, viruses and spores.|
|Hyprelva SL - non-aggressive on metal after thinning||Glutaraldehyde and cocobenzyldimethylammonium chloride.||Storage room disinfection: by spraying or thermal incineration, 1%, minimum contact time 30 min. without rinsing. Pre-cleaning!||Bacteria, viruses, fungi and yeast|
|Menno TerForte - corrosive to metal||Dimethylammonium chloride (312g / l)||1%||Against bacteria, fungi|
|Ambionet is corrosive and oxidizing. Contact with galvanized surfaces and polyamide fibers is not recommended||Glutaraldehyde (175 g / L) + Didecyl-dimethyl Ammonium chloride (50 g / L) + N-alkyl-benzyl-dimethyl Ammonium chloride (40 g / L).||Spray / Soak: 0,25% against bacteria, 0,4% against fungi, 1,5% against viruses. Rinse with water. Heat Treatment: Fumigation: 2,6L / 1000m3 /, building full of containers 3 l / 1000m 3... Contact time: 1 hour||Bacteria, fungi, viruses.|
|Ammonium 38 Master - non-aggressive, neutral pH, irritating (eyes, skin, respiratory tract)||Cocobenzyldimethylammonium chloride (32g / 100ml) + ethoxylated fatty alcohol + 2-propanol||Used for cold soaking or spraying. 0,5% solution, 5 l for 10.000 m2 contact time: 20 minutes||Bactericide, virucide, fungicide, sporicide. Attention: the product is very toxic to fish.|
All of these active substances are officially approved for use in animal husbandry, vegetable growing in greenhouses and are widely used in the Russian Federation. The most effective are Virocid and its generics. The most common and available disinfectants also include sodium hypochlorite, calcium hypochlorite, ammonium hypochlorite, chlorine dioxide, copper quinolinolate, quaternary ammonium, hydrogen peroxide and / or peroxyacetic acid mixtures. These active substances are included in preparations of various brands of different manufacturers, the differences are in the percentage of the main ingredient, the rates of use and the possibility of using the product for processing vegetables.
The choice of a disinfectant for the storage should be made based on the analysis of the following data: the hazard class of the preparation, the recommended protective equipment; restrictions on the type of surfaces to be treated (for porous or non-porous); the presence of markings “can be used for decontamination of warehouses and / or equipment for processing potatoes”, “for use only at facilities and equipment for seed potatoes”; the presence of a requirement to wash off the substance with water after treatment.
Let us dwell in a little more detail on the issue of disinfected surfaces. A porous surface is any permeable surface such as wood, insulation or dirt floor. Non-porous surfaces are defined as impervious, hard surfaces such as metal, glass or concrete. Calcium and sodium hypochlorites can corrode metal surfaces. Hypochlorites and hydrogen peroxide products are readily inactivated by organic matter and therefore not as effective when exposed to soil or wood. Clearing soil and debris is imperative to maximize the effectiveness of these active substances. When using chlorine-based compounds, adjust the pH of the solution to 6,0 - 7,5 for maximum efficiency. It is also important to avoid mixing chlorine compounds with hot water or other foods unless specifically permitted on the label.
Disinfectant is applied to all surfaces and the store is closed for two weeks. After this period, it is necessary to open the doors, ventilate and dry the room. This procedure also applies to ventilation equipment. A thorough and complete coverage of all surfaces is required, including the pressure chamber, air ducts, and the ventilation chamber.
Disinfection effectively kills pathogenic microorganisms that may be on equipment and in storage. Check the disinfectant label to see if rinsing with clean water is required after treatment. When storing seed potatoes, the storage must be cleaned especially carefully. This is of fundamental importance for storage facilities that previously used the growth inhibitor chlorprofam (CIPC). If seeds are exposed to CIPC residues, severe germination and growth retardation occurs. It is recommended to store seed potatoes no earlier than one year after the last application in the Chlorprofam store.
The storage and equipment should be kept clean at all times during the operation of the storage. Daily cleaning and tidying of work areas should be carried out. Production wastes must be removed from the storage facility and disposed of on a daily basis. In the course of long-term storage, it may be necessary to additionally disinfect problem storage chambers or product batches. This can be done by fumigation in compliance with all the above requirements. (photo 1,2).
Summary: Maintaining a constant cleanliness in the store and regular disinfection of all equipment used prevents the spread of pests and diseases and thereby contributes to the preservation of products. The list of mandatory types of work to ensure hygiene at work includes 30 items, the procedure for performing most of which should be regulated and periodically checked by an external audit. The range of disinfectants officially permitted in potato storage facilities is sufficient for effective control of pests. It is necessary to have special equipment (pressure washer, industrial vacuum cleaner, fog generators) and allocate sufficient time and resources to maintain cleanliness during storage. It is also important to take into account and observe many essential nuances of achieving maximum efficiency of cleaning, harvesting and disinfection in seed potatoes storage facilities.