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Most connoisseurs of grapes are fans of the drinkable form of this ancient fruit. There are thousands of varieties: Cabernet, Shiraz, Semillon, Chardonnay to mention just a few. Some people on the other hand are aficionados of table grapes: Sultanas, Ribier, Flame Seedless and Waltham Cross are among those readily available in our greengrocers.

Yet all these names — diverse in size, colour, taste, texture, and ripening habits — are varieties of just the one species, the European Grape. But the European Grape, Vitis vinifera, of Asia Minor origin actually, is not the only species available for SE Queenslanders to enjoy. Two American species, the Fox Grape Vitis labrusca and the Muscadine Vitis rotundifolia are available here and are worth the attention of members. (Actually, there are some dozen other native American species but we haven’t come across any in Australia other than these two).

Our interest in different species of grape arose when we lived in the relatively humid climate of the Dandenong Ranges, outer Melbourne. Traditional European varieties of grapes, both wine and table, became afflicted with downy mildew during the moist weather that lingered in the Dandenongs during and after summer rainstorms.

This same characteristic is relevant to Queensland. Although the relatively dry summer climate in the inland (e.g. Roma) and in the Granite Belt (e.g. Stanthorpe) make it possible to grow the European grapes successfully there, in coastal Queensland this is difficult, and humidity-resistant grapes do much better.

The labrusca varieties are also resistant to the root aphid phylloxera and so have been used as rootstock and hybrid partners all over the world. Many of the grapes we regard as labrusca are actually hybrids.

The labrusca varieties are distinguishable by the softer downy undersides to the leaves and less glossy top sides. Usually the leaves are less deeply dissected. The skins also slip off the fruit more easily than with the European varieties.

Flavour

Labrusca grapes are commonly described as ‘foxy’ in flavour, or typically muscat. Neither description resonates with us. Foxy apparently refers to the disagreeable flavour these grapes impart to wine, but in the fresh form disagreeable is the last description to cross one’s mind for these fine fragrant fruit. Muscat is also not a very appropriate description, as it is not unique to labrusca, for the Black and White Muscats are varieties of vinifera.

A nurseryman whom we approached for new varieties of labrusca said, the only good thing about them is that they taste so bad that the birds leave them alone. He must have been referring to the wine, as this does not apply to the fresh fruit, either for birds or, in our experience, to humans. A ripe Iona is exquisitely tasty: rich, sweet, mellow. And unless we bag or net them, we get no crop at all as the birds sample the lot before they even colour. (We have gone cool on netting since we lost a couple of bearded dragons in the net one year, so plan this year to bag every bunch).

Perhaps our friends in the Western Suburbs Wine Guild might one day submit an article on what happens to these delicious fresh fruit to give them such a bad name when converted to wine.

Varieties

Many labrusca varieties once present in Australia seem to have vanished from cultivation: Niagara, White Labrusca, Gros Colman, Wilder, Delaware, Catawba, Aurelia. Some are kept by CSIRO but there must be home gardeners in pockets of Queensland who treasure these unusual kinds.

Some varieties seem more vigorous than others: Isabella is worth growing for its luxuriant foliage alone and its stamina, even in the early part of the wet season when rain is sparse.

 We have tried the following on poor sandy soil at Bayside Brisbane.

• Isabella: the best known Brisbane grape, vigorous growth, rich purple. There is also Improved Isabella which ripens more evenly.
• White Isabella
• Pink Iona: our favourite as to taste, a pellucid pale yellow-pink skin. We also have a White Iona which is said to be more resistant to waterlogging, but we cannot distinguish the foliage habit or fruit.
• Concorde: (from CSIRO via DPI), the most popular US table grape
• Japanese Raisin
• Strawberry Grape (courtesy of Jenny Awbery)
• Muscat Flame (from Schnyder), not Flame Seedless which is vinifera;
• Lady Patricia (from Daley)
• Chambourcin (from Daley), a hybrid wine grape, one of the few to tolerate high humidity
• Golden Muscat (from Schnyder. Daley have it listed in their catalogue but have been unable to supply it in the past three years).
• Muscadine (from Daley, but they will grow it only on order and require a minimum order of 20) 

We also have some unnamed varieties.

Despite our praise for labrusca, if you still prefer vinifera grapes then in SEQ you may like to try Carolina Black Rose which seems to tolerate the humidity better than other vinifera grapes.

Exchanging Material

We would be happy to provide cuttings of Isabella and Iona to any members within Queensland but our specimens of the other varieties are not yet vigorous enough to prune heavily. Also, please note that grapes may not be sent interstate without a phytosanitary certificate (a precaution against phylloxera).

We would also be willing to travel or pay expenses to collect scions of any labrusca varieties that we are missing.

Cultivation

Cuttings are collected when vines have completely lost their leaves. Take cuttings from year old wood and cut them 40-50cm long, about pencil thickness. They may be kept in the fridge crisper after wrapping in damp newspaper inside a plastic bag. Plant in winter, leaving only about 2 buds above the surface so that a good root system is developed.

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Rain, Rain, Rain!  That’s what you can expect at Mullumbimby anytime of the year.  Reputed to be the second wettest place in Australia, and already this wet season, they’ve had 2.67m. Mullumbimby is about 1½ hours south of Brisbane, and a short distance north of Byron Bay. A good number attended the grafting course, forty-nine in all, mostly from the Sub-Tropical Fruit Club in Brisbane.  To everyone’s delight it was a beautiful sunny day – apart from two brief showers – just to remind us we were in Mullumbimby!

Chester Dott and his wife, Ketut, hosted the day and it was a pleasure to be in their company and enjoy the warmth and hospitality of their home and place of business. The day began with Chester giving a thorough explanation of all the materials and tools associated with grafting and budding.  This included grafting tapes, plant I.D. tags, plastic bags to cover new grafts, and the correct sharpening of grafting knives and plane blades. Following this, we were taken on an orchard walk for the purpose of learning how to select grafting wood.  Chester took selections of Carambola, Black Sapote, Mango, White Sapote, Longan, Wampi, Star Apple and Citrus.  These were promptly defoliated by secateurs, tagged, and wrapped in moist newspaper so that on return to the house there was no confusion about variety, and no dried out wood. After the walk we were all ready for a bite to eat, and eat we did! For a small cost we were treated to a delicious Indonesian vegetarian lunch, prepared by Chester’s wife, Ketut, and a friend visiting for the day.  I didn’t know what I was supposed to eat first, but it didn’t matter – it was all fabulous (as it turned out I ate the dessert first!) How would you go cooking hot food for 49 visitors to your house?  Well, they did and everyone was well satisfied.  The black sticky-rice pudding with coconut cream was a big hit with me! If the food was fabulous, equally was the view from the front veranda where we ate.  In the near distance were the picturesque valleys of Mullumbimby neatly framed by the nearby huge Ice Cream Bean trees and in the far distance the majestic Mt. Warning National Park with its unmistakable peak of Mt. Warning.  Talk about an appetizer! After lunch Chester demonstrated the grafting techniques for the selections he had made on our walk.  He told us he can graft up to 400 plants a day if he has help moving plants into position. Unfortunately, we ran out of time to see a demonstration of an orchard tree being “top-worked”.  This is where the branches are pruned back hard, and another variety grafted onto the tops of the cut limbs or shoots growing from the cut limbs.

The following are a few points of interest that I noted throughout the course of the day:

1.    The best times to graft are the days leading up to a full moon.

2.    Most grafting or scion wood should not be refrigerated but used as fresh as possible. 

       The exception is deciduous trees like: persimmon, fig, apples, pears and stone fruit.

3.    Use methylated spirits to sterilize grafting tools.

4.    Put a dab of grafting paint on the top of the scion or any open cuts in graft area.                     

       This is to prevent disease, & to stop the scion from drying out.

5.    To grow seedling apples for rootstocks use Granny Smith seeds. This applies anywhere on the East Coast.

6.    When grafting a tree already growing in your yard/orchard, do your graft on the sunny side.  This gives a better success rate                  .

7.    Fast growing plants/rootstocks don’t need any leaves below the graft union eg. White Sapote, Mango,  

8.    Avocado. Carambola, etc.  Slow growers like Macadamias, Black Sapote should have some leaves retained on the rootstock below the graft, if possible, to improve success rates.

9.    A graft can be done anywhere on a tree.  On most nursery stock, the graft is found on the lower part of the trunk.

10.  Keep soil dry when grafting/budding citrus.

11.  Longans have very hard wood so use a small plane to make angle cuts on scion and rootstock.  Graft October and late March (Spring & Autumn) Longans are very difficult to graft successfully.

12.  Sapodilla – graft in hot weather.

13.  Ringbark (cincture) branches of Longans and Macadamias to be used for scions.  Leave on tree for up to two months to build supply of sugar in the scion.  This will improve chances of a better success rate.

14.  Choose vigorously growing young rootstocks when grafting.

15.  Don’t overwater the rootstock because when you cut the top off the tree to do the graft, the roots are not able to take up the excessive moisture.

16.  Don’t let the cut surface of the rootstock dry out. If it does, then recut a little off immediately prior to doing your graft.

It was late afternoon when we finished the workshop and folks were keen to get home, but then we had to pass by the nursery.  Now who in their rare-fruit-mind can pass through a nursery of exotics without a bit of a gander!  Yes, I bought a couple!  One, a native I’ve been after, an Atherton Oak that bears edible nuts and a grafted Rollinia.  This cultivar is a selection by Chester that comes highly recommended.  All his grafted selections are prefixed with the nursery name “Forbidden Fruits” indicating place of origin.

This was a rare opportunity to learn from someone who has been in the business a long time.  I’m sure all who attended, appreciated Chester’s willingness to share some of his hard earned experiences with us, making our path to learning a little easier.

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We all know sugar causes tooth decay. It’s our aversion to the idea of the dentist drilling at our teeth to treat tooth decay that helps many of us resist lollies, soft drinks and other sweet treats. With this in mind, many of us reach for a glass of juice rather than a can of soft drink. But is this really any better for your teeth? Not always, says Professor Laurence Walsh, as it’s not just the sugar in drinks that’s the problem. Many of our favourite drinks, especially juices and soft drinks, contain acids that can dissolve the hard structures of your teeth (the enamel and any exposed roots), leaving the inner parts of teeth exposed, which leads to sensitivity. “That’s why if people drink either large amounts of orange juice or are regular users of soft drink, they start to notice that their teeth get sensitive as the acids dissolve the outside structure of the teeth,” Walsh says. This dental erosion is common and research has found it affects up to 43 per cent of adults and up to 80 per cent of children. While dark cola drinks are the worst offenders when it comes to dental erosion, Walsh says some highly acidic juices – such as lemon, lime or orange juice – can do more damage to your teeth than other soft drinks.
 

Acids Citric acid, which is commonly found in most soft drinks and especially in acidic juices, is one of the biggest offenders, Walsh says. Besides softening the outer teeth, it can also soften the internal parts of your teeth (the dentine), and reduces your saliva’s ability to repair your teeth.  “It steals away the calcium molecules that you normally find in saliva. By doing this, it makes the saliva unable to repair areas where minerals have been lost by exposure to acid.” In addition to citric acid, some drinks (especially dark cola drinks) contain phosphoric acid. Walsh says these two acids combined are more resistant to saliva’s neutralising effect. Lemon-flavoured cola drinks also include tartaric acid, which can also cause damage. Juices and soft drinks also contribute to dental erosion by making the mouth more acidic, providing the perfect growing environment for the bacteria that causes dental cavities. And before you reach for a sugar-free soft drink, you should know they also contain the same acids as other soft drinks. You should also watch out for sports drinks because they have similar ingredients to juice and soft drinks, and often when you drink them, you are dehydrated and your teeth don’t have the protective effects of saliva.

Protecting your teeth
Walsh says you can neutralise acids from these drinks by rinsing your mouth with tap water, drinking certain still mineral waters (the ones with bicarbonates, which neutralises acid) or chewing sugar-free gum. It may seem counter-intuitive, but if you have these drinks, the worse thing you can do is brush your teeth. Wait for at least half hour because brushing will do even more damage to the already softened enamel. You can also enjoy your favourite drink occasionally and avoid damaging your teeth if you:

Have your drink with a meal Don’t sip your drink over several hours Drink soft drinks and juices through a straw (so the liquid bypasses your teeth) Drink water in between meal times. It’s also worth remembering that the best health drink is water.

If you limit other drinks to occasional treats both your teeth and the rest of your body will thank you.

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The Earth gets its heat from the Sun. From sunrise to sunset, radiation from the Sun falls on the Earth heating the ground. The ground heats the air in contact with it which, in turn, heats the air above that. At the same time, the warm Earth is radiating heat out into space. During the day, the amount of radiation received greatly exceeds that being sent out so things warm up. As the Sun gets lower in the sky in the afternoon, the amount of radiation falling on the ground decreases until, about 3-4pm, the amount of radiation going out equals the amount coming in. That is the time of the maximum temperature. After that, the incoming radiation is less than the outgoing and the temperature falls. After sunset, the incoming radiation ceases but the outgoing continues and the temperature falls further. At sunrise, the incoming radiation starts again and a few minutes after sunrise the incoming and outgoing radiation are equal again. This is the time of the minimum temperature. Things start warming up again after that. The radiation out from the planet is from solid surfaces such as earth, rocks, plants, water droplets in clouds etc. These radiate more or less than each other. Some surfaces lose heat quickly while others do so more slowly. Smooth shiny surfaces lose heat faster than rough surfaces such as bark. As the ground cools overnight, it cools the air immediately in contact with it. This, in turn, cools the air above that and so on. As the ground continues to cool so the air near the ground is colder than the air above it. This is called a temperature inversion.

Water vapour in the air is in a constant state of flux with evaporation and condensation taking place all the time. If the rate of evaporation exceeds the rate of condensation, the air is clear. If the rate of condensation exceeds the rate of evaporation, the excess water is deposited as dew or forms fog or cloud.  The temperature at which the rates of condensation and evaporation are equal is called the dewpoint. At this temperature the air is said to be saturated and there is 100% relative humidity. Above the dewpoint evaporation exceeds condensation. If the temperature falls below the dewpoint, condensation exceeds evaporation. In winter, the dewpoint can be close to or below 0°C. If the temperature falls below the dewpoint at these temperatures, the excess water vapour does not condense to form dew but changes from the gas, water vapour, to the solid phase, ice, without going through the liquid phase. These icy deposits are frost. Frost forms on the coldest surfaces first so smooth car windscreens, which radiate heat better than rough surfaces, get the first frosts. Sometimes there will only be frost on the car, not on the plants but once frost starts to deposit on the grass and the plants,   it usually works from the ground upwards. This is because the coldest air is usually close to the ground. Air temperature as reported by the Bureau of Meteorology is measured in a thermometer screen. The bulbs of the thermometers are 1.5m above the ground. As the coldest air is below the thermometers, the air temperature can be 2-3°C while there are frosts on the ground. The Bureau considers an air temperature of 2.2°C in a thermometer screen to be the frost level minimum temperature. With that temperature in the screen, it is probable that there is frost on the ground. All this takes place on calm, clear nights. If there is wind, it mixes the cold air near the ground with warmer air above it (remember the temperature inversion) raising the temperature. If there is cloud, the cloud absorbs some of the outgoing radiation and re-radiates it in all directions including back to the ground thus raising the temperature. It is unlikely you will get frost on a windy or cloudy night. Even a full moon can provide enough radiation to lift the surface temperatures. We are only looking at frost here. Cold blasts from the Antarctic, cold enough to drop snow on the ranges are another matter altogether but, fortunately, these seldom occur in the subtropics. Sometimes the air is very dry. Temperatures fall as usual but the temperature does not fall below the dewpoint. This means there is no deposition of frost but with temperatures below freezing, plant material will freeze. This is often called a black frost and can be devastating even though no white frost has been seen. How can we minimise the effect of frost?  There are various methods and I will discuss a few of them. Cold air is denser than warm air. If you are on the top or side of a hill, the cold air close to the hillside caused by the ground radiating is denser than the warmer air away from the hillside. The denser air rolls down the hill into the valley being replaced by warmer air.  You can avoid many frosts by planting near the top of a hill rather than in the valleys. Unfortunately a really bad frost will hit the hilltops too so it isn’t 100% reliable. Remember the natural frost preventers, wind and cloud? Wind mixes the cold air with warmer air above raising the temperature. Farmers do the same by lighting fires in the corners of their fields to create convective currents that will mix the air. Asparagus farmers have been known to hire helicopters to fly up and down the fields mixing the air. It works. Large fires and helicopters might work on farms but might annoy the neighbours in a smaller suburban setting. If money is no object, those large space heaters would do a good job. Cloud prevents frost by absorbing and re-radiating the outgoing radiation. Greenhouses do the same thing. Build a greenhouse over your orchard and your frost problems will disappear – but that is impractical. Most fruit trees really only need protection when they are small. Once they are two or three metres high, they are away from the coldest air which is on the ground and they are protected at the lower levels by bark.  For one or two trees it is quite practical to build portable greenhouses out of clear plastic sheeting and conduit pipe. Igloos and tepees are good shapes. Pop the igloo over the young tree when frosts are expected and take it off when the temperature rises in the morning. As the plastic is clear, it would be safe to leave it during the day but these things are light and a good wind will destroy them. Even so, they are inexpensive and it is worth experimenting with them until the plants are big enough to look after themselves. A really bad frost will defeat the greenhouse but it should protect the plants from most frosts. Frost prevention, therefore, falls into two areas. Either mix the cold air at the ground with warmer air above or prevent the radiative cooling. I have suggested some ideas, you might think of others.

Sheryl: I saw some clear plastic pallet covers which would cover your trees against frost $17.50 each.                                                          

Steve retired from the Bureau of Metrology – NSW a few years ago. He also has degrees in Anthropology and Linguistics.

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“Food irradiation exposes certain types of food to a source of ionising energy. Under the standard covering the irradiation of food in Australia, this energy can be in the form of Cobalt 60-sourced gamma rays, machine-generated X-rays, or an electrically generated electron beam”  (www.consumersonline.gov.au/content/food/Irradiated.asp).  Irradiation does not significantly increase the temperature or change the physical or sensory characteristics of most foods. An irradiated apple will still be crisp and juicy. However, irradiation cannot be used with all foods. It causes undesirable flavour changes in dairy products and it causes tissue softening in some fruits, such as peaches and nectarines.

How does it work?

All ionizing radiation is able to remove an electron from an atom or molecule making it highly reactive. The reactive molecules react with other molecules damaging the cell’s molecular machinery and processes. Most cellular machinery can be effectively repaired. However high doses can be sufficient to destroy cells outright. Cells in the process of replication are more severely affected than other cells. The molecular damage:  Inhibits sprouting; Delays ripening and ageing; Kills or sterilises some insects and parasites; Reduces the levels of bacteria and therefore increases shelf life.

Methods
1. Electron beam irradiation
“Electron beam irradiation uses electrons accelerated in an electric field to a velocity close to the speed of light. Electrons do not penetrate the product beyond a few inches, making it necessary to treat fruit and vegetables individually; on the other hand, treatment times are only a few seconds.” (Wikipedia).

2. Gamma radiation
“Gamma radiation is radiation of photons in the gamma part of the spectrum. The radiation is obtained through the use of radioisotopes, generally cobalt 60 or in very few cases cesium 137. It is the most cost-effective technology and is preferred by many processors because the good penetration enables administering treatment to entire industrial pallets or totes, greatly reducing the need for material handling. A pallet or tote is typically exposed for several minutes depending on dose.” (Wikipedia).

3. X-Ray irradiation “Similar to gamma radiation, x-rays are a lower-energy substitute for the former. These systems are scalable and have good penetration, with the added benefit of using an electronic source that stops radiating when switched off. They also permit very good dose uniformity. However these systems require a great deal of electrical energy when operating, and exposure times are longer than with gamma rays.”

“Radioactive materials usually release alpha particles (helium nuclei), beta particles (quickly moving electrons or positrons) or gamma rays. Alpha and beta rays can often be shielded by a piece of paper or a sheet of aluminium, respectively.” “Gamma rays are less ionizing than either alpha or beta rays, but protection against them requires thicker shielding. They produce damage similar to that caused by X-rays such as burns, cancer, and genetic mutations”. (Wikipedia).

The energy waves are not retained in the food just as food cooked in a microwave oven or teeth and bones that have been X-rayed do not retain those energy waves.

Dosage    

Levels of absorbed radiation are currently measured in kiograys (kGy). The scientific community has defined three levels of food irradiation:

• Low dose up to 1kGy – kills insects on fruit and grain and kills or prevents the maturation of Trichinella • Medium dose 1-10 kGy – kills most of the bacteria that cause foodborne illness (1.5-3.0kGy for poultry)

• High dose 10+kGy can sterilize meat and other foods and decontaminate herbs and spices.

Is it new?  
The process was patented for food preservation in 1905 by a French scientist. American research began in 1921 when the U.S. Department of Agriculture (USDA) reported that irradiation would effectively kill trichinae in pork. Since then, it has gradually gathered momentum with improvements in the technology and the need for new methods to combat foodborne illness. http://www.fmi.org/media/bg/irradiation.pdf

Nutrient loss 
Many of the molecules our body requires can be made (nouveau) from the broken molecular bits and pieces absorbed via our digestive tract. However there are some nutrients we can’t make from scratch. Most animals don’t need to eat Vitamin C because they can make it. We have the genes to make it but one does not work due to mutation. We therefore need to consume food containing Vit C to remain healthy. There are many nutrients we cannot make from scratch so it is important that our food contains them.

A joint FAO/IAEA/WHO study concluded that ‘food irradiated to any dose appropriate to achieve the intended technological objective is both safe to consume and nutritionally adequate’. The Australia New Zealand Food Safety Council (ANZFSC) stated that irradiated foods will not have any significant impact on the average dietary intakes of essential vitamins and minerals. Charlotte P. Brennand, PhD, Extension Food Safety Specialist March 1995 FN-250.8 states, “nutritional losses are less than or about the same as cooking and freezing”.
Most sources approximate 5- 10% of Vitamin C is lost due to food irradiation.

Vitamin	Non-irradiated sample	Irradiated sample
Vitamin A (international units)	2200	2450
Vitamin E (milligrams)	3.3	2.15
Thiamin (milligrams)	0.58	0.42
Riboflavin (milligrams)	2.10	2.25
Niacin (milligrams)	58.0	55.5
Vitamin B6 (milligrams)	1.22	1.35
Vitamin B12 (milligrams)	21	28
Pantothenic acid (milligrams)	13	17
Folacin (milligrams)	0.23	0.18

Table 1. Vitamin content comparison of cooked chicken (irradiated and not irradiated). Amounts are for 2.2 pounds (1 kilogram) cooked chicken. Reference: Journal of Food Processing and Preservation 2:229, 1978.

Radioactive food Some people are concerned that irradiated food will be made radioactive. “Radioactivity [is the] disposition of some elements to undergo spontaneous disintegration of their nuclei associated with the emission of ionizing particles and electromagnetic radiation, as alpha particles or Beta particles and gamma radiation” (Henderson’s Dictionary of Biological terms 10th Edition Eleanor Lawrence). According to Charlotte P. Brennand, PhD, Extension Food Safety Specialist “the ionizing radiation used by [food] irradiators is not strong enough to disintegrate the nucleus of even one atom of a food molecule”.   The irradiation process involves passing food through an irradiation field; however, the food itself does not ever contact a radioactive substance.

Don’t be concerned about “interesting human mutations” occurring as a result of eating irradiated food. Food irradiated in the standard way cannot pass on radioactivity let alone radioactivity that will cause DNA damage.

It is physically impossible for food to become radioactive due to the process of food irradiation just as your teeth do not become radioactive after you have had a dental X-ray. Irradiation is radiant energy. It disappears when the energy source is removed.

Genetically damaged food
“Interesting human mutations” will not occur as result of eating genetically damaged food. A genetic mutation cannot be caught like a cold.  Depending on the type of irradiation used, DNA within the food may or may not be damaged. “Gamma or neutron irradiation is often used in conjunction with other techniques, to produce new genetic lines of root and tuber crops, cereals and oil seed crops. New kinds of sorghum, garlic, wheat, bananas, beans and peppers are more resistant to pests and more adaptable to harsh climatic conditions. In Mali, irradiation of sorghum and rice seeds has produced more productive and marketable varieties.” http://www.uic.com.au/peac.htm.

Radiolytic contamination                                                                                                              
Any kind of treatment causes chemical changes in food and that includes irradiation. The substances produced by irradiation are called radio-lytic products just as the chemicals produced by cooking could be called thermo-lytic products.

“Irradiating meat can produce benzene” and “irradiating carbohydrate-rich foods can yield formaldehyde”. Radiolytic products can be found in “cooking, canning and pasteurisation”. “At prescribed dosage levels irradiation produces small amounts of such compounds”. http://www.fmi.org/media/bg/irradiation.pdf
Scientists find the changes in food created by irradiation minor to those created by cooking. See Charlotte P. Brennand, PhD, Extension Food Safety Specialist March 1995 FN-250.8 or look up Cytochrome p450 enzymes (multi-purpose enzymes that often handle thermolytic products and more).

If you are serious about not eating irradiated food because of radiolytic products you should be serious about giving up cooked food.

Some people are concerned that irradiation will result in the formation of stereoisomers. Stereoisomers are molecules that are constructed with the same atoms but the arrangement differs in such a way that the molecules are mirror images (of each other) that cannot be superimposed (just like a left and right hand). A left-hand glove does not fit a right hand. This property is known as chirality. All but one of the 20 naturally occurring amino acids (building blocks of proteins) are chiral and are made naturally in a ‘left-handed’ form. Molecules of natural sugars are almost all made naturally in the ‘right-handed’ form (including the sugar that occurs in DNA). When molecules are manufactured in a biological system usually only one of the stereoforms is made (eg. ribose is usually made right-handed) however whenever these molecules are synthesised artificially, approximately 50% will be one stereoform and 50% will be the other. This can be a problem for the body as it is prepared to handle the naturally occurring form. This is what happened in the Thalidomide fiasco. One of the Thalidomide stereoisomers can be easily cleared by the body the other is not easily cleared. Nowadays regulated pharmaceuticals have the non-biological isomer product removed so that the body can remove the drug.

So if you are worried about irradiation because of stereoisomer formation then you shouldn’t be buying unregulated tablets or capsules of Vitamin E, synthesised amino acids or synthesised sugars unless you know the stereoisomers have been removed.

Old molecules synthesised biologically are known to flip (to the other isomeric form) for no apparent reason.

So if you are concerned about stereoisomers you should think twice about consuming any ‘old’ food eg. herbs that are not freshly picked.

The problems with stereoisomers are well known and regulated in the pharmaceutical industry. Since irradiation is regulated I would hope any problem of stereoisomer formation would have been taken into consideration. “Independent scientific research on the subject [radiolytic products produced by food irradiation] has been extensive, leading to endorsement of food irradiation by the US Food and Drug Administration, the United States Department of Agriculture and the U.N. World Health Organization as a safe, effective process”.  “The effects of food irradiation have been studied for over 60 years.” Wikipedia.

What irradiated foods are currently approved in Australia and New Zealand?   Approval was granted in September 2001 for the use of irradiation on herbs, spices and herbal infusions for control of microbes and for reduction of pests of quarantine concern.  In March 2003 the Food Standards Code was changed to allow the irradiation of the tropical fruits: breadfruit, carambola, custard apple, litchi, longan, mango, mangosteen, papaya and rambutan as a pest disinfestation measure for pests such as the fruit fly. The permission is for irradiation to a maximum of 1 (kGy) from machine-sourced electron beams or x-rays, employing Good Manufacturing/Irradiation Practices. Irradiated tropical fruits require mandatory labelling.

http://www.foodstandards.gov.au/mediareleasespublications/factsheets/fac…

Irradiated Foods Overseas:
More than 50 countries have approved irradiation for about 50 products according to the International Atomic Energy Agency (IAEA), and 33 are irradiating foods and spices commercially.

Chile irradiates about 130 metric tons (mt) per year, mostly spices, according to Nordion. Russia treats 400,000 mt each year, mostly to eliminate insect infestations from imported grain coming into its port of Odessa. China irradiates garlic to prevent sprouting and Japan treats potatoes for the same reason. France irradiates poultry to control contamination. http://www.fmi.org/media/bg/irradiation.pdf.

Conclusion: Fresh is best but I would not say “no” to an irradiated apple.

Sites of interest:

http://www.foodstandards.gov.au/mediareleasespublications/factsheets/fac…
http://www.consumersonline.gov.au/link.asp?URL=http://www.foodstandards….
http://www.dakibudtcha.com.au/Narangbah%20Irradiation%20Plant.htm

Note from Sheryl:   Tirsha has been an active member of our Club for a number of years and is also a member of the Skeptics, The Mycological Society of Queensland, a bookclub and other organisations. Her background is in biochemistry, genetics, aviation, minerals and education. She is currently a ‘Project Scientist’ at CSIRO at Pullenvale.

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At the SE Strawberry Expo at Greenville, NC and the Carolina Farm Stewardship Association Conference at Boone, NC this past November, many growers expressed interest in nutritional plant health products new to this region. I am excited about such unique supplemental plant health products. Some, for soil application, contain enzymes that will cause a great increase in soil’s natural population of bacteria to improve soil structure, water and air permeability and help unlock bound-up currently unavailable soil nutrients. Some, for drip irrigation to roots, improve plants without applying more nitrogen. Some, formulated for foliar application, provide fastest plant response. All are designed to supplement your soil improving fertility program. Several are OMRI certified for organic growers, some now are formulated with food-grade nutrients for sustainable, non-toxic use. With improvements in plant absorption technology, use of food-grade nutrients prevents plant absorption of heavy metals or other impurities that may be contained in non-food grade nutrients, and/or toxins that could become part of the fruits or vegetables that we would consume. Look for this information on the product labels!

For many years, horticulturists and agronomists have largely subscribed to the belief that foliar feeding of plant nutrients is an idea of dubious merit. A commonly held opinion is that foliar nutrients feeding is best employed only where a specific minor element deficiency may exist as determined by tissue test of plant foliage or leaf petioles. Dramatic and fast correction of such nutrient deficiencies are generally always seen from such foliar applications. Dr. H.B. Tukey, renowned plant researcher and Head of Michigan State University’s Department of Horticulture back in the 1950’s, working with research colleague S.H. Wittwer at MSU, first proved conclusively that foliar feeding of plant nutrients really works. Researching possible peaceful uses of atomic energy in agriculture, they used radio-active phosphorous and radio-potassium to spray plants, then measured with a Geiger counter, the absorption, movement and utilization of these and many other nutrients within plants. They found plant nutrients moved at the rate of about one foot per hour to all parts of the plants. Comparing efficiency of plant use of foliar-fed nutrients versus soil-applied nutrients near roots, they found foliar feeding provided about 95 percent efficiency of use compared to about 10 percent of use from soil applications! Likewise, speed of absorption and use by foliar applications was immediate, whereas from soil applications absorption and plant use both were very slow, thus providing a major benefit of foliar feeding where a specific plant nutrient deficiency may exist, be it major or minor plant nutrient.

You’ll note from references of these researchers’ work cited at the end of this article, that this very important finding was published, but only in research journals and symposia proceedings. These findings rarely found their way into the ranks of Extension educators or their grower-focused publications and other teaching materials or programs. I am living proof of that, nor was this information taught in my academic classes way back in the late 1950¹s and early Œ60¹s. Now, a half-century later, I believe it is important to bring these science-based findings to light and publicize this work to benefit growers and their crops. Armed with this knowledge they dug out of the research journals, commercial agricultural chemists began developing foliar feeding formulations.

Their continuous product improvement research has resulted in products containing not only specific plant nutrients, but also natural plant sugars that aid rapid entry and movement into and through plants, plus cytokinins: natural plant growth hormones extracted from seaweed, now stabilized for several years of shelf life. Together with nutrients, they aid natural plant defense mechanisms to resist many plant diseases and insect pests. We know that healthier plants, like humans, are better able to resist many pests compared to those in stressed, poor condition. Also, growers know and observe that the weakest plants are the ones most often attacked by many insect, disease and mite pests. I believe such products can help improve your soil and your plants’ health for higher yields with lower pest control inputs and plant nutrients costs, based on my tests over the past year and ongoing at our farm. Remember, a relatively small amount of plant nutrients, foliar-applied, can replace a much greater amount that is soil-applied, and is immediately available to plants. The development of a low-cost, natural soybean oil-based adjuvant for use with such foliar-applied nutrients and crop protectants further improves leaf and stem coverage and retention for about $2.50/acre per application. An example, combined with foliar (or even to twigs and stems after leaf drop) potassium to benefit berry, grape and tree fruits plants in late fall/early winter, or during winter in milder areas when applied anytime temperatures are above freezing: To toughen/harden plant cells, apply one gallon per acre of foliar-formulated potassium. In two weeks apply a second spray of two gallons of foliar K per acre. Add 1 pint/acre of the soybean oil adjuvant first to the tank, then a small amount of water while agitator is running, then add the potassium product and fill tank with water with agitator running, then spray. 1 gallon of the potassium per acre plus 1 pint of adjuvant oil per acre costs about $18.50 per acre per application for materials, is rain-fast in 15 minutes and is great insurance at very low cost for high-value horticultural crops. Note: Use only 50 mesh screens at the spray tips so the cytokinins will pass through to your plants. With clean spray water, I also can remove my tip screens and can also use larger spray tips to insure no clogging. For smaller areas foliar applications for 4 gallon backpack sprayer, use 1 ounce of the spray oil in 1 quart of water, stir, then add 16 oz. of the foliar potassium, stir, then fill tank with water while stirring. Shake tank from side to side while applying to maintain agitation to prevent settling. Do NOT apply this program through drip irrigation systems, as this product is formulated for foliar use only. Seaweed extracts may clog

some drip irrigation filters. A clear potassium solution is available for drip irrigation and also supplies no plant-tenderizing nitrogen in the fall or winter.
References cited for further reading: 1. Tukey, H.B. and Wittwer, S.H., 1956. The entry of nutrients into plants through stem, leaf and fruit, as indicated by radioactive isotopes. Progress in Nuclear Energy Biological Sciences Scries Six, pp. 106-114. McGraw-Hill. New York and Permagon Press, London.      2. Tukey, H.B., Wittwer, S.H., Teubner, F.G., and Long, W.G., 1956. Utilization of radioactive isotopes in resolving the effectiveness of foliar absorption of plant nutrients. International Conference on the Peaceful Uses of Atomic Energy, Vol. 12: 138-148. United Nations, N.Y.      3. Witter, S.H., Teubner, F.G. and McCall, W.W. 1956. Comparative absorption and utilization by beans and tomatoes of phosphorus applied to the soil and foliage. Proceedings, American Society for Horticultural Science. (needs vol and pp numbers from Barden).

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Here goes….mind you I am not an expert, just an informed amateur.

Green bean can be kept with little trouble or preparation for years. In fact, the green bean, like wine, changes with age and becomes more complex as it ages! This is not the case for roasted beans. Whole roasted beans will deteriorate noticeably within two weeks irrespective of how they are stored. There is much debate over how to store roasted beans: we don’t, so we don’t have a storage problem. Ground roasted beans will start to deteriorate noticeably within a day! In days gone by, every country house would roast their own beans on a daily basis with small hand cranked wood fired roasters. Small urban roasters operated in urban areas to service neighbourhoods. It was only for the second world war that mass produced instant coffee was prepared to keep the troops happy. This led to the decline in the standard of coffee as a drink overall.

There is a whole story in itself on the roasting side of the preparation. First crack, second crack and where to stop the roast. Cinnamon, City or Viennese are the names of these roasts. Then there is blending or not, and the differences in taste between the beans themselves….perhaps not this article. We roast our own with a lovely machine that allows you to see the beans darkening and to hear the cracks of the beans to determine the stage of roast. Lots of fun and you can experiment and blend and vary the roasts and get very technical and really impress your guests as you demonstrate the “art” of roasting. It certainly is a talking point.

Once roasted we tip the beans into our grinder and only grind as we need to. The grinder has a hopper on top and a “dosser” to drop a measured amount into the cup/strainer in the handle of the group head (the heated mass of metal that the handle attaches to). At this stage the important issue is to get a consistent measure of coffee into the cup/strainer so that the rate at which heated water (at 95 degrees C) passes through the group head is perfect. The resistance to the pressure of the water should be such that in less than 30 seconds you get 30ml of expressed coffee. Sounds easy you say…..well it can be once everything is set up, here are some of the things that affect the porosity of the ground coffee: the bean type, roast, grind fineness, moisture content of the ground coffee, amount of ground coffee in the cup/strainer, the pressure at which the coffee is pressed into the cup/strainer, the pressure of the heated water that passes through the handle, the type of strainer etc. The main aim is consistency so you should try to keep as much constant as possible and vary just a few of the variables so that you get a consistent 30ml in 30 seconds. We adjust the fineness of the grind (easily adjusted on a good grinder) and keep everything else constant, that is until we decide I want to try some different roasts. We stopped using a double spout handle because it was so different to the single spout handle (quantity of coffee in the cup/strainer and the resistance of the sieve itself) that we needed two different grind sizes….a pity but we get consistent coffee doing it the way we do.

Finally, the milk should be heated to no more than 60 degrees otherwise it gets scalded and it tastes well …scalded. We use a thermometer, but at a pinch we could use our finger on the metal jug as we heat it up.

Thermometers are cheap and easy to use.

We have invested in a manual coffee espresso machine that is robust, does NOT use a thermo block heating element and has a good steam and separate hot water (95 degrees ) outlet for tea or heating our cups. From our research and experience, fully automatic machines are a good way to show off to your friends that you have no idea about good coffee; manual machines are the way to go.

We love our coffee. We grow it, pick it, pulp it, dry it, hull it, roast it, grind it, express it and finally drink it. It is a journey and like all good journeys it is about the experience, but after all this experience it is nice to relax with a great coffee.

Sheryl: I was recently visiting Peter and Ann and got to taste their home made coffee. There is a difference – a huge difference so give some serious thought to giving the process a go.

Peter makes the best coffee I have ever tasted so I asked him to write something up for us.

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I ran across the Brazilian site and here’s a sample of the content. Impressive “out-of-the-box” growing technique. It is important to stress that vine citrus trees are not really vines. Instead, they have drooping branches unable to support themselves. The plants, therefore, have a willow- or umbrella-type canopy. Their branches do not climb like vines nor have special structures to attach themselves to a support structure. The development of citrus trellises, therefore, are quite different than those for grapevines, for example. Vine citrus trees should be planted at 5 to 7 feet spacing, at about 1.5 feet from the posts towards the interior of the trellis. These posts have to be spaced 10 feet between rows, 5 to 7 feet within post lines, and should be 7 to 8 feet tall. Vine citrus trees should be conducted as a single or double stem until they reach the full height of the trellis. Any lateral branch below this should be removed. These stems should be topped immediately above the trellis and allowed to branch out in all directions. These branches will be supported by beams regularly spaced over the lateral posts. The collection of such willow-type canopies will form the vine citrus trellis. Fruiting occurs along the extremities of the drooping branches and the fruit develop below the foliage with beautiful visual effects. Today,in addition to the vine orange variety, we have tangerine and lemon varieties with drooping branches thanks to breeding done at Citrolima citrus nursery. It is important to stress that vine citrus trees are not really vines. Instead, they have drooping branches unable to support themselves. The plants, therefore, have a willow- or umbrella-type canopy. Their branches do not climb like vines nor have special structures to attach themselves to a support structure. The development of citrus trellises, therefore, are quite different than those for grapevines, for example.Vine citrus trees should be planted at 5 to 7 feet spacing, at about 1.5 feet from the posts towards the interior of the trellis. These posts have to be spaced 10 feet between rows, 5 to 7 feet within post lines, and should be 7 to 8 feet tall. Vine citrus trees should be conducted as a single or double stem until they reach the fulll height of the trellis. Any lateral branch below this should be removed. These stems should be topped immediately above the trellis and allowed to branch out in all directions. These branches will be supported by beams regularly spaced over the lateral posts. The collection of such willow-type canopies will form the vine citrus trellis. Fruiting occurs along the extremities of the drooping branches and the fruit develop below the foliage with beautiful visual effects. Today, in addition to the vine orange variety, we

have tangerine and lemon varieties with drooping branches thanks to breeding done at Citrolima citrus nursery.

‘Natal’ Christmas Trees. ‘Natal’ is a very common sweet orange variety in Brazil and its name means ‘Christmas’. So Natal trees means Christmas trees. Of course we also have Valencia, Hamlin, Navel or any other citrus-type Christmas trees. The fact is that the mini-citrus-trees produced by CITROLIMA have been used in the end-of-the year decorations as tropical Christmas trees. They are grafted on Flying Dragon rootstock, a trifoliate-type citrus originated from China, and cultivated into 4 gallon (15 l) pots using composted Pine bark as growing medium. The mini-trees bear fruit regularly. They are kept under full sun but tolerate extremely well up to 30 days indoors, which makes them well suited for the new Holiday decoration. General care is very simple. The potted plants are light and can be easily moved around, giving a tropical touch to the celebrations, which occur in the summer in the Southern hemisphere. The fruit are under full development in December, have a dark green color and a little over an inch (3 cm) in diameter.

Budwood Thermotherapy  The first plants produced with citrus budwood hot treated against the bacteria of Citrus

Variegated Chlorosis (CVC) in 1994 have reached bearing age. The results are better than expected since tree vigor and productivity seem to be also above normal. This indicates the process may have additional benefits other than simply freeing the stock of bacteria. The treatment herein developed is similar to the hot bath used for rootstock seeds and consists in submitting budwood to temperatures above 125 degrees F (52 degrees C) for at least 10 minutes. Treatment parameters vary with budwood variety, physiological stage, and mass.

Budwood Storage  New methods for cold storage of citrus budwood are maintaining the quality of the propagation

material for up to 6 months. Mature budwood is cut, treated with benomyl fungicide, superficially dried and stored in cotton-cloth bags inside plastic bags. The material is inspected fortnightly, abscised petioles removed and the budsticks superficially dried again. Fungicidal treatment is repeated every 2 months. Temperature oscillates between 4 and 8 degrees centigrade ( 39 and 46 degrees Fahrenheit). Budwood may thus be kept for up to 2 years or more with the objective of preserving genetic material only, since bud take is commercially inadequate after the sixth month.

New Layout for Citrus Greenhouses  Citrolima trials have shown significant advantages for transversal bench-

arrangement in citrus greenhouses when compared with the traditional longitudinal layout: better air circulation, lower temperature, easier tree handling, easier worker circulation, and smaller, more manageable number of trees per bench. The main effect is the reduction in ambient temperature as a result of increased air circulation through the lateral screen walls, which have the entire height free at each bench interval. The resulting reduction in the number of plant containers that can be accommodated in the greenhouse is largely compensated by the derived benefits.

Dark Antechambers  Tests carried out in our nurseries indicate that dark antechambers utilized in the citrus screen

houses are advantageous. Dark chambers are built with black screens instead of clear or white ones. The screen at the door to the greenhouse should also be dark, whereas the antechamber door should be clear. The purpose is to avoid attracting insets into the chambers. Should any insects penetrate the chamber, on the other hand, they are attracted to the

clear exit door, thus facilitating their elimination.

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Distribution
Sunda Shelf (Borneo, Sumatra, Malay Peninsula, Java), Sulawesi, West Papua

Description
Chempedak is a wild and also widely cultivated fruit tree of Malaysia and Indonesia. The tree grows to 20 metres (m) in height, in wet tropical lowland and montane forests to 1200 m a.s.l. (4000 ft.). Although symmetrical and conical in shape in nature, in cultivation it is often irregular. All parts of the tree contain latex. In appearance chempedak fruit is similar to jakfruit (Artocarpus heterophyllus), to which it is closely related, in a sub-group of the breadfruit genus. The green, yellow or orangish brown skin is divided into small hexagons and either smooth or covered with small protrusions. It is cylindrical in shape, 25 to 45 cm long by 10 to 15 cm across, 1-6 kg in weight. Like the jackfruit, it is a syncarp, composed of fleshy arils or segments, 30-45 mm across, colored pale yellow, yellow, orange or green. Each aril surrounds a seed. Texture is firm, somewhat fibrous, sweet and rich. Compared with jackfruit, chempedak is sweeter and has less acidity. It has a strong aroma. Consumers like its light and delicate texture. The seeds, 15-25 mm across, are also edible, and an outstanding resource. Unlike jackfruit seeds, they have a thin, edible seedcoat.

Agronomy
The chempedak tree is rapid growing, and does not require a lot of care except in the early establishment phase, where microclimate control (shade, irrigation and staking) is recommended. When a few metres tall, however, full sun is recommended, since trees overshaded will grow too tall for easy harvest. Gliricidia works well as a companion, being gradually cut out as the chempedak nears maturity. The smaller version fully-grown tree is 9-12 m tall, and bears most of its fruit on the lower branches and trunk. Chempedaks vary in yield, however very heavy crops are common. Selected cultivars can be grafted onto chempedak or jackfruit, but seedling propagation is usual. Trees fruit in 3-5 years from planting out.

Problems
Young trees have thin stems, and may be damaged by wind. The bark is subject to disease attack, and tree surgery may be required in later years. Insects are not usually a problem because the leaves are protected by wiry hairs, and the immature fruit has latex in it. However fallen or hanging fruits are attractive to wildlife, especially Brush turkeys in Queensland, and perhaps similar megapodial birds or omnivorous mammals elsewhere. Since some fruit are borne close to the ground, ungulates may consume them directly.

Harvest
If there is an over-supply, the fruit may be picked early and consumed as a vegetable like jackfruit. For ripe consumption, size of protuberances or smoothness of skin in some cultivars, change of skin colour, and yellowing of the peduncle (fruit stem) are all guides to maturity. The fruit peduncle will easily break at the dehiscing point and the harvest fruits, with their long thin peduncles can be ripened at home or stored for later market sale. Cool room storage will extend life. The season lasts about 6 weeks, but different districts may come into season earlier or later depending on latitude and altitude. Close to the Equator two seasons may occur.

The Future
Chempedak has great promise as a “new” tropical fruit outside its current area of distribution. It has heretofore been eclipsed by its better-known “big brother,” jackfruit. However many of those who know jak will immediately be attracted to chempedak. As a backyard or orchard tree it can provide valuable carbohydrates, protein and vitamins. The fact that it has two separate, different-tasting components makes it even more appealing. As a tree crop it can replace a portion of the starch and protein in one’s diet otherwise requiring annual cropland.

On the agronomic side, N.B.Mendiolo, A.J.H.Corner and Roberto Coronel have all reported on the interchangeability of jack and chempedak characteristics. In Queensland the Malaysian cv “China” (pron. “cheena”) is sold as a hybrid between the two species. Coronel (1983) considers this apparent natural hybridization “a hindrance to rapid propagation of chempedak and popularization of its culture,” and suggests future clonal propagation.

How to Use Chempedak
Apart from raw consumption of the arils and cooking quite immature as a vegetable, there are delicious ways to prepare chempedak.

Chempedak Fritters This is a delicious and complete food. Ingredients: Batter for deep frying; whole arils with seeds still inside; flavourings to taste.

Method: Dip arils in batter and deep fry until seed is cooked–about 10 minutes. Serve plain as snack, at market or roadside stall or with rice and vegetables on the side.

Chempedak Seeds The uses of these are only limited by the consumer’s imagination.

Preparation: Remove from arils. Boil until a fork can break a seed, or a little less if using following recipe.

Fried Chempedak Seeds
Method: Fry boiled seeds in a pan with shallow oil. Don’t remove seed coats. With care, they will come off seeds and become nicely crisped. Time of frying can be varied to taste. Light frying gives a starchier taste. Breaking of seeds with implement and longer frying results in a dish like hash-brown potatoes.

Food Value Approximate Nutritional Composition (Dry weight): Protein Fat Carbohydrate Flesh 3.5-7.0% 0.5-2.0% 80%

Seeds 10-13% 1.0% 80%

Reference: Coronel, R., 1983, Promising Fruits of the Philippines, Laguna: College of Agriculture, University of the Philippines at Los Baños Chandlee, D.K., 1988, Artocarpus, Newsletter of the Rare Fruit Council of Australia, No.53, June

Allen, Betty Molesworth, 1975, Common Malaysian Fruits, Kuala Lumpur: Longman (pp.iii,25)