CONTROL AND/OR MONITORING OF THE CONDITION OF PLANT MATERIAL

Abstract: The control and/or monitoring of the condition of fresh fruit and vegetables by means of a carrier, such as a label, which supports a composition. The composition may be a naturally occurring microorganism such as trichoderma or an indicator which changes colour in response to emissions from fruit and vegetables.

Description: CONTROL AND/OR MONITORING OF THE CONDITION OF PLANT MATERIAL This invention relates to the control and/or monitoring of the condition of plant material and more particularly the control and/or indication of the condition of fresh fruit and fresh vegetables. It is well known to provide for the preservation of food products, especially fresh produce, by creating an atmosphere in the container within which the food is stored which will counter the effect of fungi, bacteria and other harmful micro organisms. For example it is now well established practice to provide a sulphur dioxide atmosphere in containers of fresh grapes in order to prevent the development of botrytis on the skins of the grapes. While these known methods have had some success they are not without problems. For example, although sulphur dioxide is effective to control botrytis it can at the same time have a detrimental effect on the fruit causing discolouration of the fruit and thus reducing its marketability. Other materials which have been proposed for preservation of fruit and vegetables such as "Benlate" are increasingly subject to official restrictions and cannot be used in all circumstances, for example its registration for use in the United States has been revoked. There is, therefore, a requirement for a means of preservation of fresh fruit and fresh vegetables which is not subject to the above-mentioned objections. It has been known for some time that fungi of the genus trichoderma are effective to control or eliminate certain micro organisms and pathogens harmful to plants. In particular formulations of trichoderma have been used to spray fruit in order to control the growth of mould thereon. The great advantage of using trichoderma is that it is essentially a biological control method and as such is not among the aforementioned methods which are objectionable to the authorities. On the contrary trichoderma or an active ingredient thereof, 6-pentyl -pyrone is approved of as a food additive or flavour modifier. However, spraying fruit with trichoderma formulations or dipping fruit therein is not always a convenient way of treating fruit and vegetable items. When fruit has been picked it needs to be processed as quickly as possible in the packhouse and placed in cold storage so that the opportunity for deterioration is kept to the minimum. The provision of an additional treatment step, that is to say the spraying or dipping of fruit increases the processing time. Additionally it increases the processing costs. Fresh fruit and vegetables as conventionally offered for sale often give no indication of their ripeness or maturity. Of course, it is possible to obtain a rough idea about ripeness from the general appearance of the fruit, for example the colour, but a more precise evaluation of the condition of the fruit or vegetable can normally only be obtained by eating it. Retailers do not as a rule permit purchasers to test the condition of fruit and vegetables in that way apart from small fruit items such as cherries, currants and the like. For larger items like tomatoes, apples, melons and avocado pears the purchaser must buy the produce without having more than a vague idea as to its condition. The major metabolic process taking place in harvested fresh produce is known as respiration. This can be described as the oxidation breakdown of the more complex materials normally present in cells, such as starch, sugars and organic acids, into simpler molecules such as carbon dioxide, water and minute amounts of other volatile substances with the concurrent production of energy and other molecules which can be used by the cell for synthetic reactions. Respiration rate of produce is an excellent indicator of metabolic activity of the tissue and this in turn is a useful guide to the potential storage life of the produce. In a significant group of fruits that include apples, pears, tomatoes, mangos, melons, papaya, avocados and bananas there is a pronounced increase in respiration known as a respiratory climacteric which coincides with the ripening of the fruit. This group of fruit is known as the "climacteric class" of fruit to distinguish it from other fruits which comprise the "non-climacteric class". The respiratory climacteric, as well as the complete ripening process, may proceed while the fruit is either attached to or detached from the plant. Avocados for example are normally harvested when mature but not ripe with the ripening process allowed to develop and this is why during the post harvest period it is usually not possible to eat avocados until they have ripened. On the other hand, citrus fruits are non-climacteric and exhibit only slight changes in internal quality after they are harvested, although they do sometimes show considerable peel colour change during this period. It has been clearly established that all fruits produce minute quantities of ethylene during development. However, coincident with ripening, climacteric fruits produce much larger amounts of ethylene than non-climacteric fruits. The present invention has been made with these points in mind. According to one aspect of the invention there is provided a carrier supporting a composition for combatting disease, infection, mould pathogen or the like in fresh fruit or vegetables and/or for preservation of fresh fruit or vegetables and/or for indicating the condition of fruit or vegetables, said carrier being adapted for application to fruit or vegetables. The invention also provides a method for the control of and/or indication of the condition of fresh fruit and vegetables comprising contacting said fruit or vegetables with a carrier as defined above. In accordance with the one preferred embodiment of the invention where control of disease and/or preservation of fruit or vegetables is required the composition preferably comprises a micro organism such as trichoderma or other naturally occurring materials such as essential oils or an active ingredient thereof or a product derived therefrom. Essential oils which can be used in the invention include oils of bois de rose, le ongrass, lavender, Mont Blanc, melissa, peppermint, penny royal, rose, thyme, spearmint and Australian tea tree. The carrier may be in the form of a small patch or label which can be adhered to a fruit or vegetable item. The composition is preferably provided on the patch or label on the side that is to be adhered to the fruit or vegetable. If desired the said composition can be included in the adhesive on the patch or label provided that the adhesive is not incompatible therewith and provided also that the active ingredient from the composition can be released from the patch or label to the fruit or vegetable when the patch or label is adhered thereto and find its way to the site of disease or infection on or in the fruit or vegetable and/or to preserve the fruit or vegetable. Alternatively the composition can be coated on the patch or label at a location free of adhesive. Again, however, it is important that the active ingredient is released from the composition when the patch or label is applied to the fruit or vegetable and can find its way to the site of infection or disease and/or can disperse onto the fruit or vegetable or preservation thereof. For indicating the condition of fruit or vegetables the composition may be one which will react, for example an indicator to produce a colour change, in response to emissions from the fruit and vegetables. Many fruit items emit volatile esters such as methyl butanoate and ethyl butanoate. Hydrolysis of the esters to acids, preferably enzymatically enables the condition of the fruit to be readily assessed, for example by means of a naturally recurring dye or the like which changes colour in response to the presence of acid. Preferably the indicator is arranged to change colour when the amount of emitted ester reaches a level that is commensurate with ripeness of the fruit or vegetable. Enzymes which can usefully be used in this aspect of the invention include carboxylase enzymes preferably buffered to a pH of 8.0 or more and which are which are sufficiently active to hydrolyse esters at pH below 5.0 and at temperatures below ambient at which the fruit or vegetables are stored. As in other aspects of the invention the carrier may be a label or patch. Preferably the label or patch may comprise a laminate including an outer impermeable layer and a permeable layer adapted to be located between the outer layer and the fruit or vegetable items. Emissions from the fruit or vegetable item pass through the permeable layer, but not through the outer layer. The outer layer is transparent at least in part so that the condition of an indicator below the outer layer can be viewed. Where the emitted substance being monitored is an ester, an enzyme for hydrolysis of the ester is also disposed between the outer layer and permeable layer. The application of the patch or label to a fruit or vegetable item can be effected by any suitable means. However, a particularly convenient apparatus which can be used is a labelling machine of the kind described in our European Patent Application No.0113256. Thus patches or labels provided on a carrier strip of release paper can be removed from the release paper and transferred to fruit and vegetable items. Since it is now accepted practice to label such fruit and vegetable items the provision of trichoderma on such labels means that no additional processing step is required in the packhouse in addition to the steps already being carried out. It is not, however, necessary to combine trichoderma composition with a conventional label. If desired the fruit and vegetable items can have a separate patch or label with the trichoderma composition applied thereto in addition to a conventional label. Alternatively the composition can be provided on a carrier that is not attached to the fruit or vegetable items, but is placed in the package containing such items. In conventional labelling the location of the label on the fruit or vegetable items is not normally predetermined. However, it can be arranged that a patch or label having a trichoderma composition thereon can be deposited on the fruit or vegetable item at a selected location so as to be more effective in controlling infection or disease. This may require the inclusion of a means for orienting the fruit or vegetable item appropriately. The invention is not restricted to the above described embodiments and many variations and modifications can be made.

Claims: CLAIMS 1. A carrier supporting a composition for combatting disease, infection, mould pathogen or the like in fresh fruit or vegetables and/or for preservation of fresh fruit or vegetables and/or for indicating the condition of fruit or vegetables, said carrier being adapted for application to fruit or vegetables. 2. A carrier as claimed in Claim 1, wherein the composition is a naturally occurring micro organism such as trichoderma or an essential oil or active ingredient thereof. 3. A carrier as claimed in Claim 1, wherein the composition is an indicator adapted to change colour in response to emission from fruit or vegetables. 4. A carrier as claimed in Claim 1 or Claim 2, formed as a patch or label. 5. A carrier as claimed in any preceding claim, wherein the carrier is provided with adhesive in order to secure said carrier to fruit or vegetables. 6. A carrier as claimed in Claim 5, wherein the composition is included in the adhesive. 7. A carrier as claimed in Claim 5, wherein the composition is provided at one or more locations on the carrier free of adhesive. 8. A carrier as claimed in any of Claims 1 or Claims 4 or 5 as appendant to Claim 1, wherein the carrier is a laminate comprising an outer impervious layer and a permeable inner layer. 9. A carrier as claimed in Claim 7, wherein the composition is disposed between the outer and inner layers. 10. A carrier as claimed in Claim 7 or Claim 8, wherein the composition comprises a substance that reacts to emission from fruit or vegetables. 11. A method for the control of and/or indication of, the condition of, fresh fruit and vegetables comprising contacting said fruit or vegetables with a carrier as claimed in any preceding claim.

Inventors: BRIGGS PETER DAVID SINCLAIR, SAUNT JAMES EDWARD, SAYLE DEREK ANTHONY, BRIGGS, PETER, DAVID, SINCLAIR, SAUNT, JAMES, EDWARD, SAYLE, DEREK, ANTHONY
Applicants: BRIGGS PETER DAVID SINCLAIR, SAUNT JAMES EDWARD, SAYLE DEREK ANTHONY, SINCLAIR INT LTD, BRIGGS, PETER, DAVID, SINCLAIR, SAUNT, JAMES, EDWARD, SAYLE, DEREK, ANTHONY, SINCLAIR INTERNATIONAL LIMITED
Application year: 1995
Main classification: B65D79
IPC codes: A23B7, A23L3, B65D79, G01N33