Back to the Basics
By Diana J. Choyce
Oct 04 - 10, 1999
Keeping fruit crops fresh from picking to retail shelves is a well
known problem. Doing it without chemical pesticides and preservatives is an even bigger
problem. Doing it naturally would be the best solution for the growers, shippers,
retailers and consumers. Can it be done? According to research being done by Lisa Skog and
Prof. Dennis Murr, from the Department of Plant Agriculture'sVineland Research Station,
and Brian McGarvey of Agriculture and Agri-Food Canada, it's a definite possibility.
Natural fruit "volatiles" are compounds already found in
fruit and which enhance its flavor and aroma. But in high enough concentrations it can
also produce antimicrobial agents which will protect the fruit from fungal attack and
damage. In response to environmental stress, injury and microbal attack a fruit will speed
up its production of certain volatiles.
"If natural fruit volatiles prove effective, then growers,
distributors and consumers will all benefit," says Skog. "It could lead to a
healthier product, less storage decay, longer shelf life and decreased losses during
shipping." The result can also mean huge monetary savings for all involved in the
fruit business. And even more important a very positive effect for both humans and their
The main focus of researchers is to find an alternative to using
chemicals such as methyl bromide for fumigating fruit, soil, and grain storage facilities.
This chemical has been used extensively for years despite its obvious negative effect on
consumers and their environment. After January 2001 the use of methyl bromide will no
longer be available. This has put all research into natural options on the fast track. The
use of volatiles looks to be very promising. They may prove be very effective in
preventing latent infections from becoming active because they can penetrate the fruit
surface. Since not all volatiles are effective, the focus has been on identifying the most
useful ones. And then testing and evaluating their effectiveness, finding the best methods
of application, and deciding on the precise amounts to be used. So far over 20 volatiles
have been found with 5 identified as possible options.
The research is called biocontrol and involves many different levels of
study. From introducing micro-organisms to prevent infection of economic crops by
soilborne pathogens, to the use of applying fruit volatiles directly to the fruits. There
is also research being done involving genetic altering of plants to achieve these ends. In
many respects it is very similar to studies being done on humans to provide
ways to naturally fight off disease and infections. The world has
become far too dependent on chemically based answers to all these problems. And all too
often it has proven the old adage that "the cure is worse than the disease".
The use of natural means has been documented as far back as Roman
times, when the lowly mustard seed was used to preserve foods. And in the early 1900's
research was started on determining which components in the seed were producing these
preservative properties. But the research was stopped as chemical methods came on the
scene and were regarded as easier and cheaper to use. Things have now come full circle as
we have finally admitted the need to revert to natural methods in order to preserve not
only our foods but ourselves and our environment. Had these earlier studies been continued
its possible that chemical pestisides may have never taken such a hold in the world of
Another study is being done to effect a way to monitor fruit, to
determine quality and ripeness based on the emissions of volatile gases. This electronic
sensor monitoring system would be extremely helpful in harvesting, grading and sorting
fruits. A better understanding of the maturation of fruits would also be helpful in
predicting their shelf life and would be very useful to fruit retailers. It is already
being used with great success on crops such as already with apples, blueberries,
raspberries and blackberries, strawberries, tomatoes and melons.
On a side note, research is also being done that could provide a
possible treatment for HIV. This project is in cooperation with the University of Yaounde,
Cameroon, and the Cameroon government along with other agencies and institutions. The
plant being studied is the wild tropical liana from the rain forest of Cameroon, Africa.
Means of cultivating the plants, which are rich in michellamine B (a dimeric alkaloid),
and delivering them to the National Cancer Institute for chemical extraction and study are
the main focus. Given the large quantities needed in this research, special nurseries have
also been started to possibly clone these plants.
Agricultural research will no doubt provide the answers to many many
problems facing the need to feed the world populations. And providing safe, long term, and
effective means of growing, picking, packing and shipping are of the upmost importance.
The economic impact on developing countries in regards to import and export is of great
concern. And as always the effect on both humans and their environments is and should be a
long term goal. Huge amounts of time and investment will be necessary to solve these
problems. It is comforting to see that we've finally come to realize that natural methods
have always been and will always be the only alternatives we should be seeking.