The challenge for any category in the fresh produce sector is maintaining quality and freshness - and grapes is no exception. With produce being shipped from round the world, often spending weeks at a time on the water, grape suppliers must ensure their fruit reaches its destination markets in perfect condition.
The use of sulphur dioxide pads within the produce industry has played a major role in maintaining the fruit’s performance, but the recent debate over the use of sulphur on grapes put the industry on a knife-edge and exposed the inherent weakness of over-reliance on just one system.
SO2 is used to extensively on grapes, both in storage and transport, to inhibit the development of botrytis and skin discolouration.
However, its use was thrown into disarray after Norway’s food standards agency challenged the validity of sulphur residues on grapes entering the country, a challenge that was quickly backed by other Scandinavian countries.
The problem was created by the fact that SO2 is classed as a food additive and regulated by a European Directive, which was being interpreted in contrasting ways in different EU member states.
The row provoked a review of the use of sulphur, which some in the industry feared could lead to a ban on its use entirely, which would impose a significant restriction on trade flows.
A campaign was launched by industry representatives Freshfel, the Fresh Produce Consortium and other interested groups, and much to the relief of the sector, it proved successful, with an amendment to the Directive accepted by the European Parliament.
A maximum residue level of 10mg per kg has now been set for grapes and lychees, which Tom Lyall, food safety advisor with Freshfel, says was exactly what the industry was looking for.
“There’s absolutely no negative health implications at those levels, and the general residue levels on grapes is 5mg a kg,” he says.
“We welcome the clarity on the amount and it will allow the continued trade of table grapes in line with the demands of the entire industry.”
So the good news is that sulphur remains on the menu for grapes, but the issue that left the industry in the situation in the first place remains - is it safe to have all your eggs in one basket?
The answer is clearly no and the scare over SO2 has given added emphasis to the search for alternatives.
One such alternative has been proposed by Netherlands-based packaging manufacturers Kappa. Its packaging system, QuaMa, is beginning to generate increasing interest in the sector.
Martin Dunnett, commercial director with Capespan, says: “We’ve been doing a lot of work to find an alternative - and working with packaging suppliers Kappa, we’ve been doing a trial for the last three years on QuaMa.”
The packaging uses a modified atmosphere which Dunnett says is self-modifying, with a permeable membrane. “Any risk of botyritis is minimised and we’ve been very happy with the results, particularly on Flame, which gets dehydrated very easily. QuaMa allows it to hold its moisture content and slows down any development problems.”
Dunnett says the development work has now led to the creation of a 9kg pack. “Initially it was only available in the 4.5kg pack, which the retailers didn’t want, but now we’ve rolled it out into 9kg.”
He says the concept is beginning to catch on with the retailers: “Sainsbury’s is now asking suppliers to deliver a percentage of their produce packed in QuaMa this year.”
Sainsbury’s Theresa Huxley says at the moment there is very little that is offering a viable solution to sulphur pads, but QuaMa is interesting them. “We have already carried out some trial work with it and we are extending the trial further during this South African season.”
She says another key advantage QuaMa has over other grape packaging is the fact it allows the produce to presented very well.
Dunnett says it does offer a better alternative to the current methods of preservation: “Sulphur is not necessarily the best method for fruit, and QuaMa gives you much fresher product - there is no sulphur burn or fruit drop.”
However, it is not all a bed of roses with QuaMa, he points out. “There are issues, particularly for growers - it’s an added cost to pack the fruit using QuaMa, and it’s a slower process in a sector where speed to market is everything.”
Despite this however, if the demand from retailers grows, QuaMa could soon become a more common sight in the grape supply chain.
While alternatives such as QuaMa, which offer additional benefits on top of SO2, appear to be establishing themselves, not all alternatives are being pursued following the EU ruling.
Cargofresh Technologies, which was working with Brazilian researchers, has decided not to pursue its work on controlled atmosphere containers for mainstream grape exports.
Erik Dunkelmann, from Cargofresh, said the EU decision to retain the use of sulphur pads meant there was no need to progress further with trials on CA.
The company had teamed up with Hamburg Sud and Embrapa, the Brazilian agricultural research corporation, and carried out successful trials using CA storage to assess the impact on the fruit’s shelf life.
While Dunkelmann says the scheme has been abandoned for mainstream grapes, it could still be used for the export of organic fruit. “The decision on the pads means that, for the time being, CA containers are no longer necessary for common table grapes.
“But SO2 pads, are still not allowed for organic grapes, which will now be the focus for CA application on grapes.”
He says the use of CA means the stems remain greener and and anthracnose is retarded. “This could be of interest to the entire organics industry, especially since the IFOAM (association for organic produce) has recommended CA container shipment as the most suitable mode of transport for organics,” he adds.
So, while some solutions are being abandoned in favour of the tried and tested sulphur pads, other are continuing to gather pace - such as the work of Frutavit.
The Israeli company offers post-harvest solutions based on natural plant extracts. It says its solutions work by harnessing anti-oxidant and anti-microbial properties of the plants to create a natural protective barrier against discolouration, botrytis and other fungi.
The solution has been developed into a spray form, which the company says can be applied either pre- or post-harvest, and that also adds the advantage of cutting back on other fungicide spraying. Another added advantage is that Frutavit claims its solution will cost around the same as the existing sulphur pad system, adding no extra costs. At the moment the company is continuing to trial the system with Somerfield in the UK.
So, while sulphur pads might be back on the menu, the industry has broadened its options and should issues arise in the future, it is now better placed to handle them.
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