Extending storage life: what you can do if your potatoes are in store for longer than expected

Sunday, 31 May 2020

The coronavirus outbreak has completely shifted market dynamics for potatoes and has brought about many storage-related questions as a result. Read our Storage FAQs for some answers.

1. How do I store my crop longer to wait for demand to pick up?

Be vigilant for any change in quality: longer term storage can lead to more softening of tubers and may also result in other problems, such as senescent (old age) sweetening or higher levels of disease. Sprouting will be another concern and an additional dose of sprout suppressant may be required if available to the crop. Consider reducing store temperature.

Fresh Pack

If quality permits and refrigeration is available, consider reducing temperature for longer-term stored material. If necessary, consider using spearmint oil to control sprouting.

For refrigerated stores, review the likely customer/market requirements particularly for whether there will be demand to move the stock at a later date. Consider earlier movement where possible.

Crisping & processing fries

Critically, maintain a dialogue with your customers about prioritising unloading of ambient stores as we move into early summer and particularly for varieties susceptible to senescent sweetening. If you have stock remaining in store and are concerned about sprout control, an additional dose of CIPC may be required to extend storage life.

Ambient only stores that are fairly well insulated will normally be able to maintain temperatures below around 8 °C until mid-late May. After this time, refrigeration would normally be required to maintain cool store temperatures. If refrigeration is not an option and you still have stock, it is essential to move it ASAP while it still has value. For help on finding a market, visit the potato portal.

2. I have had to change my marketing plans. Can I sell processing potatoes for fresh?

Yes you can, quality permitting. The Potato Industry CIPC Stewardship Group (PICSG) recently announced that Potatoes treated with CIPC at rates between 24 and 36 g/t may now be marketed using fresh supply chains, as long as crops are tested and comply with the Maximum Residue Levels (MRL).

Take a look at the PICSG statement and CIPC MRL sampling guidelines.

3. My stores are nearly empty. What work can I be doing over the coming weeks to best prepare my stores for next season?

CIPC-treated stores must be cleaned to comply with the much-reduced MRLs expected next season. A thorough job must be done to remove all potential sources of CIPC contamination and we recommend you make a start as soon as possible.

Before store cleaning is started, you will need to carry out a risk assessment. Hazards you will likely come across include but are not limited to:

  • Inhalation of dust
  • Working at height
  • Tripping

Follow HSE guidelines on how to carry out a risk assessment.

If your store has a history of CIPC application, follow the recently released EU-wide guidelines to remove as much of the chemical’s legacy from the store as possible. 

If there is no history of CIPC application, then prepare stores as usual. More details on crop debris removal and disinfection can be found on our store cleaning page.

Basic post-storage checks include that equipment such as fans and fridges are functioning correctly.

If the system includes a fridge, check with your local service companies on their availability during the COVID-19 restrictions. If possible, book a service early to ensure your system is checked and fully up to speed in time for harvest.   They need to ensure that the fridge gas level is correct, fridge coils are clean and that condensers are working properly and outlets are clear to allow heat to be removed to outside.

Check that air ducts are unobstructed and in good repair and that lateral shutters work smoothly. Inspect louvres closely for damage or misalignment that prevents them closing fully.

Verify that sensors are accurate by comparing against a good hand held thermometer, ideally in water (at a temperature in the range the store runs at) or, alternatively, melting ice (0 °C). Tidy up sensor leads, checking for damaged or stretched cables.

It is expensive to control the air within a store and a well-sealed store minimises the cost and improves control. Check store fabric integrity, ensuring that doors seal correctly and repairing gaps where possible.

Remove any outdated chemical signage.

For any questions on storage, call the storage advice line free of charge on 0800 02 82 111 or email sbcsr@ahdb.org.uk.