Last year, potato growers learned of the impending withdrawal of the potato sprout suppressant chlorpropham (CIPC). CIPC was a vital active in controlling potato sprouting in stores. The active ingredient lost its approval on 8 January 2020. Sales in Ireland must finish and it must be removed from the shelves of distributors by 8 July.
From 8 October this year, no further use is permitted and the current maximum residue levels (MRL) of 10mg/kg for CIPC on ware potatoes will no longer hold. Instead, the MRL will be automatically replaced by an LoQ – a limit of quantification. It is not yet known what this will be, however LoQs tend to be low, at 0.01 parts per million (ppm).
CIPC is effective because it hangs around in stores for a long time. The challenge is that when potatoes that go into store, even years after CIPC was last used, they will pick up traces of it and may exceed this LoQ.
As a result, the industry is looking for a temporary operational limit which is workable in the short- and medium- to long-term. CIPC approval holders have requested this temporary MRL (tMRL), and while we know the European Commission has been investigating this, it has not yet announced a decision.
In the UK, research done by Sutton Bridge Crop Storage Research (SBCSR) on 11 stores found that CIPC residue levels of approximately 0.4 mg/kg were detected for 95% of sampled stores. It is anticipated that any tMRL, if granted, will have a similar value.
Store cleaning
Potato store managers have an important job to do in reducing CIPC levels left over from previous applications in order to meet any forthcoming tMRL for future crops.
To assist store managers across the continent in complying with this, the European Potato Value Chain, a group of industry bodies, has produced guidelines for reducing CIPC in potato stores. Store cleaning should begin as soon as the 2019 crop has been unloaded. Below are the key cleaning principles. The key cleaning areas are outlined in Figure 1.
Figure 1. Key cleaning area and principles in potato stores.
Inside the store
1 Cleaning activities must integrate safety parameters. Always use personal protection equipment (PPE) and pay attention to safety when working at height. 2 Keep written records and pictures of what has been cleaned, how and when. The buyer of the potatoes may request a record of cleaning activities. 3 Cleaning must be carried out from top to bottom (ie roof to floor). Preferably use dry cleaning methods inside the store and in any case start with them. Only if no suitable dry cleaning method is available, or not sufficient for complete cleaning, should water be used. When using complementary wet cleaning, an acceptable method of collecting water and disposing of it appropriately must be used to avoid dispersing waste water into the environment.4 Care should be taken to minimise re-distribution of CIPC. Loose materials should be removed promptly, by vacuuming. Sweeping and brushing generate dust, which risks redistribution. 5 CIPC is only slightly volatile. Volatilisation will contribute to removal of CIPC, but over longer periods of time. When the store is not in use for potato storage, doors and hatches should be left open to allow for continuous refreshment. 6 Underground ducts should also have a constant movement of air after cleaning, either by running fans or by natural draft. Low airspeed is sufficient. 7 Clean all loose materials by brushing and vacuuming together (not in sequence, but always combined) from all critical areas in the store. For stubborn deposits, more aggressive methods maybe required (wire brush).8 On floors and walls, use brushes with hard bristles to scrub, eg steel or hard plastic, so it will release particles attached to concrete and other store fabrics. On exposed insulation with a rough surface, often on ceilings, use softer, longer bristles to better remove particulates and not cause damage on foam.9 Use a vacuum cleaner with a robust dust filter (HEPA, M-filter (99.9%) or carbon filter) so even any very small fine CIPC particles are not released back into the store. Change or clean the filter regularly.10 In the most contaminated places (plenum, fans, refrigerating units), the use of a high-pressure steam cleaner with integrated suction is recommended to complement dry cleaning.11 Clean your cleaning tools (brooms, brushes, etc) using high-pressure water.Wooden boxes
Remove all loose materials by brushing. Consider a subsequent wet cleaning method using a box washer, but take care of water disposal. Store boxes outdoors for the entire period that the boxes are not in use. Boxes should not be close-stacked. Take care that boxes are stacked safely.Far, transport, hoppers, conveyors, store loaders and box fillers
Outdoor wet cleaning with high-pressure water on a specific area where waste water can be easily collected is sufficient. Special attention must be paid to hoppers and conveyors used for CIPC dust or liquid applications during store loading operations.Lorries used for transportation
Brush out before wet cleaning with high-pressure water with appropriate waste water collection and disposal.
Hotspots
Hotspots depend on the type and location of CIPC application and on the fog distribution within the store when hot-fogging practices were carried out. Carefully consider the places where CIPC fog was applied and hotspots where accumulated deposits may be found which were not removed by regular cleaning during the past seasons (floor and wall near fogging port, plenum, fans, refrigeration unit, roof-heater fans, anti-condensation fans etc).
Last year, potato growers learned of the impending withdrawal of the potato sprout suppressant chlorpropham (CIPC). CIPC was a vital active in controlling potato sprouting in stores. The active ingredient lost its approval on 8 January 2020. Sales in Ireland must finish and it must be removed from the shelves of distributors by 8 July.
From 8 October this year, no further use is permitted and the current maximum residue levels (MRL) of 10mg/kg for CIPC on ware potatoes will no longer hold. Instead, the MRL will be automatically replaced by an LoQ – a limit of quantification. It is not yet known what this will be, however LoQs tend to be low, at 0.01 parts per million (ppm).
CIPC is effective because it hangs around in stores for a long time. The challenge is that when potatoes that go into store, even years after CIPC was last used, they will pick up traces of it and may exceed this LoQ.
As a result, the industry is looking for a temporary operational limit which is workable in the short- and medium- to long-term. CIPC approval holders have requested this temporary MRL (tMRL), and while we know the European Commission has been investigating this, it has not yet announced a decision.
In the UK, research done by Sutton Bridge Crop Storage Research (SBCSR) on 11 stores found that CIPC residue levels of approximately 0.4 mg/kg were detected for 95% of sampled stores. It is anticipated that any tMRL, if granted, will have a similar value.
Store cleaning
Potato store managers have an important job to do in reducing CIPC levels left over from previous applications in order to meet any forthcoming tMRL for future crops.
To assist store managers across the continent in complying with this, the European Potato Value Chain, a group of industry bodies, has produced guidelines for reducing CIPC in potato stores. Store cleaning should begin as soon as the 2019 crop has been unloaded. Below are the key cleaning principles. The key cleaning areas are outlined in Figure 1.
Figure 1. Key cleaning area and principles in potato stores.
Inside the store
1 Cleaning activities must integrate safety parameters. Always use personal protection equipment (PPE) and pay attention to safety when working at height. 2 Keep written records and pictures of what has been cleaned, how and when. The buyer of the potatoes may request a record of cleaning activities. 3 Cleaning must be carried out from top to bottom (ie roof to floor). Preferably use dry cleaning methods inside the store and in any case start with them. Only if no suitable dry cleaning method is available, or not sufficient for complete cleaning, should water be used. When using complementary wet cleaning, an acceptable method of collecting water and disposing of it appropriately must be used to avoid dispersing waste water into the environment.4 Care should be taken to minimise re-distribution of CIPC. Loose materials should be removed promptly, by vacuuming. Sweeping and brushing generate dust, which risks redistribution. 5 CIPC is only slightly volatile. Volatilisation will contribute to removal of CIPC, but over longer periods of time. When the store is not in use for potato storage, doors and hatches should be left open to allow for continuous refreshment. 6 Underground ducts should also have a constant movement of air after cleaning, either by running fans or by natural draft. Low airspeed is sufficient. 7 Clean all loose materials by brushing and vacuuming together (not in sequence, but always combined) from all critical areas in the store. For stubborn deposits, more aggressive methods maybe required (wire brush).8 On floors and walls, use brushes with hard bristles to scrub, eg steel or hard plastic, so it will release particles attached to concrete and other store fabrics. On exposed insulation with a rough surface, often on ceilings, use softer, longer bristles to better remove particulates and not cause damage on foam.9 Use a vacuum cleaner with a robust dust filter (HEPA, M-filter (99.9%) or carbon filter) so even any very small fine CIPC particles are not released back into the store. Change or clean the filter regularly.10 In the most contaminated places (plenum, fans, refrigerating units), the use of a high-pressure steam cleaner with integrated suction is recommended to complement dry cleaning.11 Clean your cleaning tools (brooms, brushes, etc) using high-pressure water.Wooden boxes
Remove all loose materials by brushing. Consider a subsequent wet cleaning method using a box washer, but take care of water disposal. Store boxes outdoors for the entire period that the boxes are not in use. Boxes should not be close-stacked. Take care that boxes are stacked safely.Far, transport, hoppers, conveyors, store loaders and box fillers
Outdoor wet cleaning with high-pressure water on a specific area where waste water can be easily collected is sufficient. Special attention must be paid to hoppers and conveyors used for CIPC dust or liquid applications during store loading operations.Lorries used for transportation
Brush out before wet cleaning with high-pressure water with appropriate waste water collection and disposal.
Hotspots
Hotspots depend on the type and location of CIPC application and on the fog distribution within the store when hot-fogging practices were carried out. Carefully consider the places where CIPC fog was applied and hotspots where accumulated deposits may be found which were not removed by regular cleaning during the past seasons (floor and wall near fogging port, plenum, fans, refrigeration unit, roof-heater fans, anti-condensation fans etc). 
This is a subscriber-only article
SHARING OPTIONS: