Does Your Olive Oil Have "Too Much" Linolenic Acid ?

A largely ignored component, linolenic is one of the minor fatty acids found naturally in olive oil. Linolenic acid does not affect the flavor or keeping qualities of olive oil.  The International Olive Oil Council (IOOC) has requested that the Codex Alimentarius, the world food standard setting body, change the definition of olive oil to exclude oil which has a linolenic acid level greater than .9%.  Currently the level is set at 1.5%.  The reasoning is that olive oil adulterated with high linolenic hazelnut or canola oil would be easier to spot. 

Australians and New Zealanders think the real reason for the change is to exclude their oils from the international market.  The EU may be threatened by large mechanized farms in Argentina and Australia which will soon be producing large quantities of inexpensive extra virgin oil. Climatic conditions in the Southern hemisphere tend to naturally create olive oils high in linolenic oil.  If these oils cannot be legally called olive oil they would only be allowed to be labeled "fruit juice".  The Australians have argued that changing the standard represents a non-tariff trade barrier.

According to the commission, The Codex Alimentarius  was created in 1963 by FAO and WHO to develop food standards, guidelines and related texts such as codes of practice under the Joint FAO/WHO Food Standards Programme.

The Codex also limits the upper and lower permissible levels of the three most common fatty acids found in olive oil: oleic 50-85%, palmitic 7-20%, and linoleic 3-20%.  Factors which affect the percent of the different fatty acids include latitude, climate, variety and stage of maturity of the olives.¹  According to studies done by Lotti et al²,  olive fruit from cool areas contain oil with more unsaturated fatty acids than fruit from dry and warm areas.

Delay in harvesting can also change fatty acid ratios; later oils have more unsaturated fatty acids, especially linoleic, instead of palmitic.  Other studies have shown that year of harvest may have the most effect.  European olive oil producers take advantage of this in blending commercial oils so that they do not exceed the Codex limits.

Linolenic acid contains 18 carbon atoms and three double bonds and belongs to the beneficial omega-3 family of fatty acids. An essential fatty acid which cannot be produced in the body, linolenic acid is converted to the precursors of prostaglandins and thromboxane which help decrease inflammation and blood clotting in the body.

Australia and New Zealand's lobbying efforts have led to a hold on changes to the Codex pending further input from interested parties.

1. Boskou, Olive Oil Chemistry and Technology

2. Lotti, G., R. Izzo and P. Riu.  Effects of climate on acid and sterol composition of olive oil .  Riv. Soc. Ital. Scien 11:115 (1985)

University of California Olive Production Manual
Book Review

The Olive Production Manual was first printed in 1994 when there were only a handful of  California olive oil producers.  While originally oriented toward canning olives,  it has been the bible for many getting started in the oil business. Now that there are hundreds of olive oil producers and the industry has matured, the much anticipated second edition has been released.

Editors Steven Sibbett and Louise Ferguson are well known to olive farmers from their presentations at olive industry events. 

For some, the new edition will not meet expectations. It is evolutionary in nature with many sections nearly identical to the original edition. There are welcome additions about the olive fly, newer harvesting methods, and a rewritten section on olive oil production, but much of the information which the authors and contributors have presented in lectures and presentations over the years has not been included.

The original manual was 147 pages, the new one weighs in at 174 pages.  The history chapter presents updated charts and information about some of the newer varietals being grown although county data is still over 10 years old. 

Propagation information has been expanded with extensive information about rooting cuttings.  In the pruning section there are new sections reflecting the introduction of shakers and vertical rotating comb harvesters, although no mention of the over the row harvesters used by California's biggest grower.

Watering sections are expanded with new methods for determining soil water levels. A new chapter describes the effects of water stress on olive tree performance.

The olive disease and pest sections are pretty much the same with the addition of the pages on the olive fly.

In the Harvesting chapter, the biggest change has been the removal of pages of economic analysis of mechanical harvesting.  It has been replaced with the puzzling sentence, "Cost projections for mechanical harvesting have not been developed".  This despite many economic  presentations over the years from U.C. experts at Olive Day.

A large discussion of the abscission process has been removed in the new edition.  Storage of fresh olives is elaborated in the Processing chapter. 

The biggest and most welcome change for olive oil producers is in the olive oil production section. U.C. extension expert Paul Vossen has completely rewritten the chapter with practical information gleaned from his years here in California and in his travels to Spain and other olive oil producing countries.  The 15 page chapter is a great review of olive oil making from history to marketing. 

Our biggest disappointment is the mass of valuable information about olive oil making that has been presented over the years by U.C. experts that has not been included. That said, the new edition is well worth its modest price of $35.  The new color plates would by themselves justify replacing your old well thumbed manual.

To purchase the Olive Production Manual call 1-800-297-4434 or go to the university website 

Time for Olive Fly Trapping

Most California olive farmers will have set out traps for olive fly by the end of March for control or monitoring purposes.  The McPhail trap which contains a reservoir of fluid bait has been show to attract many more times more flies than sticky traps.

An easy and inexpensive attractant is Torula yeast tablets. One tablet is used for every .4 liter of water. The tablets take 2-4 days to ferment and start releasing compounds which attract the fly. More water should be added to the traps when the level drops below 1/3 of the original due to evaporation. The solution lasts  from 4-8 weeks before needing to be replaced, depending on ambient temperature.

The traps are put on the Southern side of the tree in winter or the Northern side in summer months, hung in the shade of foliage. 10 traps per acre are suitable for monitoring purposes but for fly control, 1 trap per tree is recommended. The Olipe trap, made from a disposable plastic container, is a cheaper option.

Most olive farmers will start applying GF120 spray when the olive pit starts hardening (around the first of June) for optimal control of the olive fly.

Fly density can be recorded weekly .  For the technologically savvy, Moritor Technologies has developed a hand held device which has a GPS unit which records your location in the orchard as you enter pest data. The information can then be plotted on a site map to show where additional traps or spray should be applied.

For more information see: Moritor Technologies

15th IFOAM World Congress  20-23rd September 2005 Adelaide