Novel depot film for

happy potatoes

The dose makes the poison (see Paracelsus)...but what about our potatoes?

Potatoes belong to our basic food. In 2016 and 2017 up to 60 Kg per year and citizen were eaten in germany.[1]

Though to compete with others in the market the quality of potatoes plays an important role. Potatoes are harvested during the autumn and will be store in huge warehouse overthe winter season. To inhibit germination and keep them fresh and nutritious potatoes are treated with the germicide chlorpropham (Isopropyl-N-(m-chlorophenyl)-carbamate) CIPC.

Chlorpropham is growth regulator which is used for potato storage for over 60 years.[2]For indication the additional note „Treated after harvest“ is printed on the packaging label.Since the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) classifies chlorpropham as suspected to be carcinogenic the growth regulator is only allowed to a maximum amount of 10 mg/Kg in potatoes.

Up to this value the BfR claims no risk to health.

Previous processes used high amounts of chlorpropham to inhibit germination.Thus the potatoes are often loaded up to the maximum value of 10mg/kg and the risk of chlorpropham overloading increases significantly.[4]

Up to 95% less poison - the novel process with the depot film TUBERSERV

Researchers located in Saxony-Anhalt invented a functional film which keeps the active component chloropham as depot inside. Such products with depot and release effect are well-known in medicine (e.g. pain or heat plaster). But the main difference: TUBERSERVhas no contact with the potatoes at all!

With this novel process the legal amounts of chlorpropham can be reduced by 90% to 95 % to values of 0,5 to 1mg/kg !

Advantages of the novel process:

1. Lowering of the legal amount of 95%.2. Less labour costs per storage period, once-only mounting/unmounting of film3. No odor nuisance for the employees, reduction of hazard potential4. Reliable delivery - No waiting time

(Previous process: After nebulization warehouse is not accessible, no entry.)5. Value for money - absolutely convinced6. During complete storage time - steady & low release of CIPC - to stored material7. Ventilation mode: air circulation, forced ventilation, fresh air, temperature control, CO2

Pilot plant approachThe storage of the potato sort „Lady Claire“ was investigated as box and packed bed for a storage time of 6 months. After drying and wound-healing of the potato peel the depot film TUBERSERV was mounted.

Fig 1. Comparison of the current process using nebulization equipment with the novel TUBERSERV system mounting a depot film in packed bed/plain storages.

1. Current process with CIPC-nebulization

2. Novel process with CIPC-depot film

fresh air

nebulization with CIPC

Repeated nebulization every 4-6 weeks (8-12 g/t potatoes)

The depot film is mounted in the warehouse

only once a season and kept until the end

of the storage period (ca. 7 months)

Fig 3. Storage of potatoes on a packed/plain bed

DEPOT-FFoolliiee - Tuberserv

Abb. 1 Vergleich eines gängigen Verfahrens mit Nebelgeräten und dem Einhängen der DEPOT-FolieSchüttlager/ Flachlager

Abb. 2. Lagerung der Kartoffel in Holzkisten

DEPOT-FFoolliiee - Tuberserv

Abb. 3. Lagerung der Kartoffel auf einem Schütthaufen/Schüttlager

Während im gängigen Verfahren die Verneblung mit CIPC aller 4-6 Wochen ( 8-12g/t Kartoffeln)wiederholt werden muss, wird die DEPOT-Folie nur einmal pro Saison in die Lagerhalle eingehängt und verbleibt bis zum Ende der Lagerperiode dort.

Die Folie wird über die eingelagerten Kartoffeln, wie z.B. in einem Schüttlager, eingehängt. ImKistenlager ist zu empfehlen, zusätzliche Lagen in den Zwischenräumen einzuhängen.

Durch die Luftzirkulation tritt der Wirkstoff kontaktlos gleichmäßig aus. Das Luft/Wirkstoffgemisch umhüllt die Kartoffel gleichmäßig und dringt durch den gesamten Kartoffelstapel. Es werden für 1 Tonne Kartoffeln nur 1m² Folie benötigt [3].

Abb.4 Erste Laborversuche mit der Kartoffelsorte „Linda“Lagerung: 14 Tage bei 22-23°C, 55% rel. F. Lagerung: 70 Tage bei 22-23°C, 55% rel. F.

Um die Wirksamkeit ständig beobachten zu können, lagerten die Proben bei schwachem Tageslicht,deutlich erkennbar an den grünen Stellen (Solanin). Die Kartoffeln mit der DEPOT-Folie keimten auch nicht nach 70 Tagen, trotz der hohen Lagertemperaturen von 22-23°C.

Anders bei den Vergleichskartoffeln, bei der die Folie kein Wachstumsregulator enthielt. Hier waren bereits nach 14 Tagen erste Keime erkennbar, die nach 70 Tagen zu einem totalen Qualitätsverlust führten. Die Schrumpfung der Kartoffeln, bedingt durch den Wasserverlust wegen der hohen Temperaturen, wurde in diesem Versuch vernachlässigt.

Um das Wirkprinzip unter technischen Lagerbedingungen bei Temperauren von 8-10°C und einerLuftfeuchtigkeit von ca. 80% zu prüfen, erfolgten Technikumsversuche, siehe oben.

Quelle:[1] https://de.statista.com/statistik/daten/studie/175422/umfrage/pro-kopf-verbrauch-von-kartoffeln-in-deutschland/

[2] https://apvma.gov.au/sites/default/files/publication/14731-chlorpropham-frr.pdfNRA Special Review of Chlorpropham. Australian Pesticides and Veterinary Medicines Authority, November 1997(englisch).

[3] WO2013175461A1

[4] https://www.efsa.europa.eu/en/efsajournal/pub/4903

While within the current process nebulization with CIPC needs to be repeated every 4-6weeks (8-12 g/t potatoes) the depot film TUBERSERV is mounted only once a season andkept until the end of the storage period.

The film is mounted above the stored potatoes, e.g. in a packed bed storage. If boxes areused for storage it is recommended to apply additional layers in the space between.

During air circulation the active component is evenly released. The air/component mixturecovers the potatoes uniformly and interpenetrates the potato stack completely ..For 1 ton of potatos only 1m² depot film is needed. [3]

Fig 2. Storage of potatoes in boxes

To monitor the effectiveness of the depot film the test samples were stored under low daylight conditions which is indicated by green spots (solanine) on the potato. Even after 70 days of storage with the depot film and storage temperatures of 22-23 °C no germination of the potatoes was observed

In contrast the samples which were treated with a depot film without active component already after 14 days of storage first sprouts could bee seen and led to a complete degradation after 70 days. Weight loss, or shrinkage, of the potatoes due to loss of water was neglected during the tests.

To verify the active principle under industrial conditions at temperatures of 8-10 °C andwith a relative humidity of ca. 80% pilot plant tests had been conducted (see above).

Quelle:[1] https://de.statista.com/statistik/daten/studie/175422/umfrage/pro-kopf-verbrauch-von-kartoffeln-in-deutschland/[2] https://apvma.gov.au/sites/default/files/publi ation/14731-chlorpropham-frr.pdf NRA Special Review of Chlorpropham. Australian Pesticides and Veterinary Medicines Authority, November 1997(englisch).[3] WO2013175461A1[4] https://www.efsa.europa.eu/en/efsajournal/pub/4903

Fig.4 Bench test with potato sort „Linda“

Storage conditions : 14 days at 22-23°C, 55% rel. hum. Storage conditions : 70 days at 22-23°C, 55% rel. hum.

film with chlorpropham

film with chlorpropham

film withoutchlorpropham

Film without chlorpropham