Harvest Season in Balıkesir's Olive Oil Mills

Olive oil mill safety: why is the harvest season different?

In Ayvalık, Burhaniye, Gömeç, Edremit and Havran, on the shores of Balıkesir's Gulf of Edremit, an olive oil pressing plant is quiet for most of the year but runs non-stop during the harvest. Olives cannot be left on the tree, and once picked they need to be processed without waiting long at the mill. From autumn to midwinter, this pressure brings three things to the mill at once: longer shifts, seasonal workers hired at short notice and machines that hardly ever stop. That is why olive oil mill safety starts with a plan put in place before the harvest.

There is also a specialised OIZ (organised industrial zone) for olive processing in Burhaniye; however, a significant share of the plants around the gulf are family-business scale, around villages and small towns. Because Balıkesir borders Bursa, it falls within the service area of an OSGB (joint health and safety unit) based in Bursa; we describe how we organise our visits on our Balıkesir OSGB page. Brining plants processing table olives have different risks; for them, see our article on brine and tanks in Gemlik olive plants.

Shifts, overtime and seasonal workers during the harvest

The biggest risk during the harvest is often not a machine but fatigue. The shift plan should be built within the limits of Labour Law No. 4857:

• Overtime: may not exceed a total of 270 hours a year and requires the worker's consent (Art. 41).
• Night: night work may not exceed 7.5 hours, and no overtime may be worked at night (Art. 41, 69).
• Daily limit: even if weekly hours are distributed unevenly across days, daily working time may not exceed 11 hours (Art. 63).
• Shift change: a worker whose shift is changed may not be put on the other shift without at least 11 hours of uninterrupted rest (Art. 69).

Some of those working as olive harvest workers in the groves also start work at the mill when the harvest intensifies; the rules do not change for these seasonal workers either. Every new worker receives at least 2 hours of face-to-face, practical induction training before starting work, documented with a signed record; basic training is completed within 3 months of starting work at the latest. A person who worked the previous season and has had a break of more than 6 months receives refresher training on job-specific risks. In hazardous and very hazardous work, a worker may not start without a fitness-for-work report. For how to manage shift fatigue, see our article on shift systems and fatigue management.

Olive reception, washing and crushing line

Olives unloaded from the lorry go into the reception hopper, then by screw conveyors and elevators to the leaf-removal fan and the washing machine; they are then turned into paste in the crusher.

• Reception hopper: there is a risk of falling for anyone climbing onto the lorry bed or working at the edge of the hopper. A grating is fitted over the hopper mouth and guardrails along the edges; fixed steps are used to climb onto the lorry bed.
• Screw conveyors and elevators: open screws and chain elevators draw in hands and clothing. Covers are kept closed; blockages are not cleared by hand while running.
• Leaf fan and washing: wet floors and olives cause slips; floors are cleaned frequently and slip-resistant shoes are worn.
• Crusher: hammer and disc crushers are among the noisiest points in the plant. If noise exceeds the upper exposure action value of 85 dB(A), wearing hearing protection is mandatory and hearing tests are carried out. We plan measurements with authorised laboratories; for the rules, see our article on the noise regulation and exposure values.

The malaxer (kneading machine) can cause serious limb injuries during cleaning and maintenance because of the paddle rotating inside. Covers and guard gratings must be in place, and the energy must be isolated and locked out before reaching inside.

Decanter safety and separators

The decanter separates the paste into oil, water and pomace with a horizontal bowl rotating at high speed; the separator gives the oil a final cleaning with a vertical bowl. Both have a large rotating mass and a long run-down time.

1. Do not open before it stops: decanters and separators keep turning for a while after being switched off. The cover is only opened once the bowl has stopped completely; interlocks and sensors specified by the manufacturer are not disabled.
2. Monitor vibration: unusual vibration or noise is a sign of imbalance or bearing failure. The machine is stopped and the maintenance team informed; the attitude of "let's finish the season and look at it then" is the most dangerous choice.
3. Maintenance and cleaning: bowl removal and separator bowl maintenance are carried out only by trained people who know the manufacturer's instructions, using special tools. The energy is isolated, locked out and tagged; for the method, see our article on LOTO lockout and tagout.
4. Hot water and steam: the boiler and pipework supplying heated water to the malaxer and separator carry a burn risk. Boilers and pressure vessels undergo periodic inspection at least once a year.

For general guarding rules on food processing machinery, read our article on safety of food machinery.

Pomace and wastewater areas

The pomace coming out of the decanter is conveyed by screw conveyors to a store, a pit or directly onto a lorry. Three-phase systems also produce olive mill wastewater, which is held in ponds.

• Pomace screw conveyor: long and often open screws carry a risk of entrapment; no section is left uncovered, and blockages are not cleared without isolating the energy.
• Pomace pit and lorry loading: guardrails are fitted at the edge of the pit; the lorry manoeuvring area is separated from pedestrians, and a banksman is used when reversing.
• Wastewater pond: falling into ponds with slippery edges can lead to drowning. The pond is fenced, warning signs are put up, and rescue equipment such as a lifebuoy is placed nearby.
• Dried pomace: heaps of pomace dried for use as fuel can self-heat and smoulder. Heap temperature is monitored, heaps are kept small and they are included in the fire plan.

Pomace oil plants, which extract oil from pomace using a solvent, are a separate type of plant with an explosive atmosphere risk because of the flammable solvent; they require an explosive atmosphere (ATEX) document.

Oil store and tank cleaning

Olive oil is usually settled and stored in stainless steel tanks.

• Entering a tank is confined space work. Before going inside to clean a tank, a work permit is issued, oxygen and gas measurements are taken and an attendant is stationed outside. For the rules, see our article on working in confined spaces.
• Nitrogen blanketing: in some plants, the headspace of the tank is filled with nitrogen to prevent the oil from oxidising. Nitrogen is odourless and colourless; in these tanks, an oxygen-deficient atmosphere is the most serious hazard.
• Tank tops: ladders and platforms used to climb onto tanks have guardrails; the risk of falling is controlled while hatches are open.
• Oily floors: oil spilt in filling and transfer areas is cleaned up immediately; absorbent material is kept ready.

We set up this calendar together with the business and review the risk assessment for harvest season conditions. For the scope of our services, see our OHS specialist service and food sector pages; to track inspection and training dates, see our OHS calendar tool.

Frequently Asked Questions

How many hours a day can workers work during the harvest?

Daily working time may not exceed 11 hours, and night work may not exceed 7.5 hours. Overtime may not exceed 270 hours a year, requires the worker's consent and may not be worked at night.

What training should seasonal workers receive?

At least 2 hours of face-to-face induction training is given before starting work and documented with a signed record. Basic training is completed within 3 months of starting work at the latest; those returning after a break of more than 6 months since the previous season receive refresher training on job-specific risks.

When can the decanter cover be opened?

Only once the bowl has stopped completely. The decanter keeps turning for a while after being switched off; the manufacturer's interlocks and sensors are not disabled, and the energy is isolated and locked out before maintenance.

Is cleaning an olive oil tank confined space work?

Yes. The inside of a tank is a space with limited entry and exit and inadequate ventilation. A work permit, oxygen and gas measurements and an attendant outside are required before entry; in tanks with nitrogen blanketing, the risk of an oxygen-deficient atmosphere is checked separately.