**9.3 Environment**

Perhaps the main issue for Australian oils was the very variable environmental conditions under which the crop was being grown. Oil quantity and quality rely heavily on crop management, moisture availability, harvest timing, processing methodology and storage. As a result of these differences Australian oils showed a wide range in the fatty acid profiles (Mailer, 2005b). The diversity in other quality characteristics and sensory analysis were also significant.

In the initial stages of the development of this industry, there was little understanding of the intricacies of these crop management practices and the resultant crop yield, chemical quality and sensory attributes such as taste, colour and odour. For these reasons, several studies have been undertaken to look at the relationship between oil quality and harvest timing, irrigation treatments, yield and sensory characteristics (Mailer 2007).

As a result of the low rainfall and unpredictable nature of the Australian environment, almost all Australian olive groves are irrigated. Irrigation provides more predictable yields and harvest timing unlike dryland groves. Due to the importance of irrigation, research has focussed on water requirements, particularly in the stages from planting to commercial harvesting (De Barro, 2005). This research has been aimed at increasing the understanding of olive water use and requirements in the period from planting to early fruit bearing. As most Australian olive groves are irrigated several studies have focussed on variation in maturity, yield, oil quality and sensory attributes under variable moisture availability (Ayton et al., 2007) and with different harvest times.

Environmental effects on oil production have created unexpected issues for Australian producers. The variation in quality and sensory has created a new spectrum of oils with unique qualities and sometimes more variable attributes than has been produced in Mediterranean climates. This sometimes results in the oil being outside the limited range of existing international standards (Mailer, 2007).

Cultivation of Olives in Australia 229

oil of that year being affected to some degree. Early frosts will normally affect the fruit leading

Although oil may be acceptable when it is processed, maintaining the quality after processing became a major consideration. Two studies carried out in 2008 by the Australian Olive Association on supermarket oils (AOA Report – unpublished) included 22 oils initially and later, a further 33 oils of random brands. The reports revealed that many oils would not pass IOC tests most likely because of poor storage or old age, although some oils were clearly adulterated. The AOA and RIRDC have funded long term storage studies under extremes of temperature, light and oxygen exposure to determine potential shelf life and develop an understanding of methods used to advise marketing on

Shelf life depends heavily on the type of material the oil is stored in. Although most experts would recommend the use of glass or stainless steel, often oil is stored temporarily in plastic bottles or collapsible bags. Studies on the effects of the different types of containers used for transport and sometimes for long term storage have been published (Mailer & Graham, 2009). The study reinforces that the best storage conditions for olive oil is in opaque, impervious and inert containers, stored at cool temperatures. Metallised flexible bags used for short term transport may provide reasonable protection. Storage in clear plastic, particularly in the light and at elevated temperatures, is unacceptable and results in loss of extra-virgin olive oil quality within a short period. Re-use of these containers is highly

Australia has been free of many cosmopolitan olive pests due to its isolation but the rapid expansion of the olive industry in all mainland states has led to increased problems with pests and diseases. The control of these problems became a focus for all growers. A report on sustainable Pest & Disease Management in Australia Olive Production (Spooner-Hart, 2005) describes sustainable management, monitoring pest and beneficial species in groves and identified a number of previously unreported pests and diseases. Further publications have included a field guide to olive pests, diseases and disorders in Australia (Spooner-Hart et al., 2007) designed as a quick reference to take into the grove and use to identify pests and

Dealing with by-products of olive oil processing is another important issue in modern agriculture. A study on recycling of solid waste from the olive oil extraction process (Tan & Markham, 2008) and a subsequent report outlines methods for developing an environmentally sustainable system to manage solid waste from the 2- and 3-phase olive oil mill extraction processes. The expanding Australian olive industry over recent years, with significant increase in fruit production, has resulted in vast quantities of solid and liquid wastes generated to the detriment of the environment. The industry is been faced with the

to significant changes in the chemical and organoleptic characteristics of the oils.

**9.6 Shelf life** 

potential shelf life.

**9.7 Pest and disease** 

diseases and the damage they cause.

**9.8 Waste management** 

undesirable and would cause more rapid degradation.

#### **9.4 Harvesting and processing**

Along with the determination of the best cultivars, the methods of harvesting and processing have been evaluated. Many types of harvesters and extractors, generally from European manufacturers, were being used throughout the industry. Hand harvesting and many types of vibrating rakes, tree shakers and accessories were unsuitable for large scale production. Larger producers investigated straddle harvesters (Fig. 3) which underwent several modifications to make them suitable. These are used widely today.

Processing also went through stages. Some producers tried mechanical mat presses or stone mills (Mailer & Ayton, 2004) in the early stages but these were never used for large scale production The majority of processors have installed modern two or three phase centrifugal extraction mills.

Fig. 5. One of the early harvesting methods adopted in an Australian olive grove.
