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Critical Control Points – EVOO

Updated – 4th July 2016

Learning from previous mistakes.

Critical control points in the production of Extra Virgin Olive Oil (EVOO) and an explanation how to use chemical and sensory testing can help producers to identify production problem areas and develop solutions.

Some Take Home Messages:

  • To be classified as EVOO a product must meet the minimum quality parameters as specified in the Australian Standard (AS5264-2011).
  • Product testing (both chemical and organoleptic) is an important diagnostic tool and a sound investment in producing high quality EVOO.
  • By producing clean, sound fruit, and undertaking rapid processing using a clean mill, growers can produce high quality EVOO.
  • Exposure to high temperature, oxygen and light at any point along the supply chain will accelerate the oxidation of EVOO, lowering product quality and reduce potential shelf life.

The following provides an outline of critical control points in EVOO production and an explanation how to use chemical and sensory testing to help producers identify production problem areas and develop solutions.

What makes for a good quality EVOO?

Research evidence suggests fresh and well processed EVOO will exceed the quality parameters as specified in the Australian Standard (AS):

  • Zero organoleptic faults (AS =0)
  • FFA’s in the vicinity of ≤0.4 (AS ≤0.8)
  • PV’s in the vicinity of ≤12 (AS ≤20)
  • K232 values under 2.00 (AS ≤2.5)
  • K268 values under 0.18 (AS ≤0.22)
  • ΔK values of less than 0.01 (AS ≤0.01)
  • PPP values around 1% increasing by 6-8% per year (AS ≤17)
  • DAG values around 90% decreasing by 20-25% per year (AS ≥ 35)

The minimum evidence of product testing that needs to be provided for each product to be certified under the Code of Practice is:

Free Fatty Acids (FFA), Peroxide Value (PV), Ultra-Violet Absorption (UV) – (deltaK, K232 &K270),

plus sensory assessment undertaken by – NSW DPI or Modern Olives (or through participation in an AOA accredited EVOO Competition).

optional but useful for establishing objective BBDs is 1,2 Diacylglycerides (DAGs), and Pyropheophytins a (PPPs).

How can this quality objective be achieved?

A) Grove best practice: healthy soil and healthy trees:

  • Olive should be handled as a fruit – the delicate nature of a ripe fruit needs to be protected from pressure, temperature, and abrasion. Breakdown of the fruit initiates the fermentation and oxidation process, leading to defective oils.
  • Control diseases and pests – any pest that directly attacks the fruit must be controlled to prevent fruit decay – some growers have bitten the bullet and removed problematic varieties.
  • Ensure chemical residues in fruit meet market MRLs and avoid product contamination (biological, chemical and physical) – Manage water quality / Phthalates are an issue in some export markets and care must be taken to use new, non-APVC food grade plastic hoses and fittings.
  • Practice good grove hygiene / develop biosecurity awareness.
  • Implement a fertiliser program based on leaf analysis / practice good canopy management – healthy soil is a foundation for healthy trees and high quality fruit.
  • A visual inspection of olives trees before harvest will identify any serious pest and disease or other fruit quality issues – best to tag these trees so that they are not harvested, or risk serious product quality issues and downgrading from EVOO to VOO or lampante classification:

Laboratory indicators of poor fruit condition:

  • Median of defects – Musty / Humid / Earthy / Grubby

Characteristic flavour of oils obtained from fruit in which large numbers of fungi and yeasts have developed as a result of its being stored in humid conditions for several days or of oil obtained from olives that have been collected with earth or mud on them and which have not been washed or those washed with dirty wash water. Character: soil, dirt.

Also exhibit high Free Fatty Acid levels (FFA).

  • Median of defects—Rancid

A flavour defect caused by the oxidation of the oil and subsequent formation of aldehydes during the production process giving the oil an oxidized flavour and odour. Character stale nuts, putty – usually accompanied by a greasy mouthfeel.

Also exhibit high Peroxide Value (PV) and igh UV Absorption K232 (indicating secondary oxidation) ow 1,2 Diacylglycerides (DAGs), igh Pyropheophytins a (PPPs).

  • Median of defects  – Frosted / Stewed Fruit / Wet Hay

From olives damaged by frost. Character: wet wood, stewed fruits, vanilla, acrylic paint, custard, aniseed.

Also exhibit high PV.

B) Post-harvest best practice bulk olive handling and storage:

  • Harvest and transport fruit with care – do not compromise the integrity of the fruit.
  • Use clean and covered bins / implement good cool chain management – avoid leaving bins of fruit in the hot sun / use of concrete aprons around sheds to assist hygiene management and a wash down facility for machinery entering the property including harvesters and pruners -/ need to be careful when stacking bins – there have been incidents where soil contaminated with termite treatment has fallen into and contaminated bins of fruit.
  • Limit the depth of containers to reduce pressure on the fruit.
  • Ground fruit is second class fruit and should be kept separate from tree fruit.
  • Do not store olives – prolonged storage of the fruit is contrary to the production of quality oil. Oxidation and fermentation occurs in the stored fruit, which can lead to defects and off flavours in the oil.

Note: In order to consistently produce high quality EVOO. Boundary Bend Ltd (BBL) have a 6 hour policy of “dwell time” between harvesting and processing. There is evidence of an inverse correlation between dwell time and oil quality.

Laboratory indicators of poor post-harvest handling:

  • Median of defects—Fusty

A flavour defect attributable to poor storage conditions of the olives before crushing, usually promoting the bacterial growth of the Clostridium and Pseudomonas genera.

Also exhibit high FFA.

  • Median of defects—Musty

A flavour defect occurring when low temperatures and high humidity promote mould growth, mainly of the Aspergillus and Penicilium genera or Anthracnose. Character: Flavour musty – mould – mouldy hay.

Also exhibit high FFA.

  • Median of defects—Winey-vinegary

A flavour defect caused by storage condition of the olives that causes aerobic fermentation by the growth of yeasts that produce ethanol, acetic acid, and ethyl acetate. Character: nail polish remover – vinegar.

Also exhibit high FFA.

C) Best practice processing:

  • Minimise time between harvest and processing / use food grade non-PVC hoses / seek out processors with high skill levels.
  • Keep Everything Clean – The failure to maintain cleanliness is a major factor in reducing oil quality since olive oil can so easily become contaminated. Odours from the fermentation of waste products can get into oils in the processing plant.
  • Clean machinery, floors, and walls will prevent rancid odours that can also contaminate the oil.
  • Cleanliness is especially important in the olive washing process where the wash-water needs to be kept clean at all times. To minimise phthalate contamination, only distilled water should be used for washing fruit and cleaning tanks. Some producers prefer not to wash fruit at all.
  • Process the Olives Quickly and at a Moderate Temperature – Quality oil comes from fruit that was worked at temperatures below 30 degrees C. This is important for protection of the aromas and reduction of oxidation. Poor quality fruit worked at higher temperatures can actually reduce certain desirable oil characteristics.

Laboratory indicators of poor processing:

  • Median of defects  – Musty – humid earthy

Characteristic flavour of oils obtained from fruit in which large numbers of fungi and yeasts have developed as a result of its being stored in humid conditions for several days or of oil obtained from olives that have been collected with earth or mud on them and which have not been washed or those washed with dirty wash water. Character: soil, dirt.

Also exhibit high FFA.

  • Median of defects—Muddy sediment

A flavour defect caused by storage in contact with oil sediment for long periods. Character: salami – parmesan cheese – vomit.

Also exhibit high FFA.

  • Median of defects – Metallic

Mouth sensation reminiscent of contact with metal. Effect usually occurs in excessively bitter oils or when oils have contacted non-inert metallic surfaces. Character: metal on fillings, Epsom salts.

  • Median of defects  – Cooked / Heated or Burnt

Characteristic flavour of oils caused by excessive and/or prolonged heating during malaxing. Character: toffee – caramel.

Also exhibit high PV and high K270 (indicating excessive heating).

  • Median of defects  Vegetable water

Flavour acquired by the oil as a result of prolonged contact with vegetable water due to wrong separation settings in the centrifuge allowing water to be collected with the oil.

Note the use of traditional mat presses is NOT recommended due to accelerated oxidation of the extracted oil – leading to rancidity, and certain off flavours from the use of mats:

  • Median of defects—Rancid

A flavour defect caused by the oxidation of the oil and subsequent formation of aldehydes during the production process giving the oil an oxidized flavour and odour. Character stale nuts, putty – usually accompanied by a greasy mouthfeel.

Also exhibit high PV and high K232 (secondary oxidation) low DAGs, high PPPs.

  • Median of defects  – Esparto Characteristic flavour of oil obtained from olives pressed in new esparto mats. The flavour may differ depending on whether the mats are made of green esparto or dried esparto.

Note: Poor mat cleaning may result in other common organoleptic faults including:

  • Median of defects – Acid-sour – from olive paste left on pressing mats which have not been properly cleaned and leads to the formation of acetic acid, ethyl acetate and ethanol.

D) Best practice olive oil handling and storage:

  • Store EVOO with care – good storage is extremely important and will permit the conservation of desirable flavour components.
  • It is fundamental to store oil in clean stainless steel with limited air space at temperatures below 18 C. / Minimise time that olive oil is stored in plastic – the continuing use of ICBs by smaller growers is of concern – suggest producers work on a ICB replacement program.
  • Frequently racking off sediments / manage storage temperature, oxygen and light exposure control.

Laboratory indicators of poor olive oil handling and storage:

  • Median of defects—Muddy sediment

A flavour defect caused by storage in contact with oil sediment for long periods. Character: salami – parmesan cheese – vomit.

Also exhibit high FFA.

  • Median of defects—Rancid

A flavour defect caused by the oxidation of the oil and subsequent formation of aldehydes during the production process giving the oil an oxidized flavour and odour. Character stale nuts, putty – usually accompanied by a greasy mouthfeel.

Also exhibit high PV and high K232 (secondary oxidation) low DAGs, high PPPs.

E) Other important considerations:

Bottling and Product Distribution

  • Ensure label compliance with AS5264-2011, The Food Standards Code Regulations, and Australian Consumer Law  including the use of BBDs supported by technical evidence / good record keeping, use batch numbers and product recall procedures.
  • Always retain batch samples for subsequent testing and always retest stock held over from the previous season to ensure it still meets the requirements of EVOO classification.
  • When buying in bulk oil – do not rely of test results provided by the seller – always obtain independent test results to confirm product quality.
  • It is highly recommended to check potential BBDs with an occasional  PPP and DAG test – to be confident of its nominal 2 year shelf life.

Staff training, retailer and customer education:

  • Become an olive oil expert – know just what it takes to produce, harvest, and process olives of high quality.
  • Staff should undertake training in sensory evaluation of olive oil and be able to recognise the major defects that can appear in olive oil.
  • Make use of the Code of Practice on-line training modules.
  • Develop a HACCP style food safety . food quality plan to assist in identifying and managing the critical control points in evoo production / keep good production records.
  • Monitor your products through the supply chain and provide retail customers with tips on product storage conditions and stock rotation.
  • Know your customers, educate them about the different classes of olive oil, and help them to enjoy this healthy food.
  • Point of Sale / Farmers Market materials are available for purchase from AOA here.

For further information please contact the Code Administrator at any time on 0476 760 160 or [email protected] Also welcome any feedback and further suggestions on critical control points based on your experiences.