Mass Food Poisoning in the Canteen: What to Do

Food poisoning at work: the first signs

A few hours after lunch, two workers from the production line come to the first aid room with nausea and abdominal pain; an hour later three more people call from the office. Looked at one by one, this seems like an ordinary stomach upset, but when it appears in several people who ate the same meal it becomes a suspected case of food poisoning at work and requires a separate process.

The main symptoms of food poisoning are nausea, vomiting, diarrhoea, abdominal cramps and fever. Depending on the agent, symptoms start anywhere from a few hours to a few days later; the first cases are therefore not everyone who will be affected. A worker with any of the following symptoms is referred to a healthcare facility without delay, or 112 is called:

Bloody diarrhoea or persistent vomiting,
Inability to keep fluids down, dizziness, marked weakness, passing very little urine,
Double vision, difficulty swallowing, slurred speech or muscle weakness,
Pregnancy, older age or a known chronic illness.

The first hour when mass poisoning in the canteen is suspected

Mass poisoning may originate in the canteen, but in the first hour the source is unknown. The first steps are therefore taken in a way that makes it possible to find the source:

Refer severe cases. Healthcare is called for those with the symptoms above; the names of those referred and the facility they went to are noted.
Stop service. Meals not yet served and the portion of the same dish set aside for the next shift are not served.
Protect the samples and leftover food. Reference samples are left in place, leftover food and the ingredients used are not thrown away, and general cleaning of the kitchen is not started.
Inform the workplace physician. If the physician is not present, the workplace nurse or first aider starts the process and contacts the physician.
Start the case list. Who ate what and when symptoms began are recorded in the first hour.
Inform the catering company and management. The company is asked to preserve its own records and samples.
Make the official notification. Suspected foodborne illness is reported to the provincial or district directorate of Agriculture and Forestry via the ALO 174 Food Line or in writing. The reports and records of the healthcare facility assessing the cases support this notification.

Case tracking: who ate what, and when did they fall ill?

The most powerful tool for finding the source is a simple case list kept by the workplace physician. The list has the following columns:

Name and surname	Department and shift	Meal and dishes eaten	Time symptoms began	Symptoms	Referral and outcome
Example worker A	Assembly, 1st shift	Soup, chicken, rice, ayran	15.30	Vomiting, abdominal pain	Observed in first aid room, sent home
Example worker B	Office	Soup, rice, salad	16.10	Diarrhoea, fever	Referred to hospital

As well as those who fell ill, those who ate the same meal and did not fall ill are asked which dishes they ate. This comparison is the fastest way to narrow down the source. A worked example: if 20 of the 80 people who ate rice fell ill, the attack rate among rice eaters is 25 per cent. If 2 of the 60 people who did not eat rice fell ill, the rate is about 3 per cent. The large difference points to the rice as the suspect dish. The same calculation is done separately for each dish and the result is shared with the official inspectors.

The times symptoms began are also informative. If cases cluster within a few hours, an incident originating from a single meal is considered; if they are spread over days, person-to-person transmission or an ongoing source is investigated. The case list contains health data; it is kept under the workplace physician's responsibility in line with the principle of confidentiality. For the rules, see our article on employee health information and KVKK (personal data protection).

Sample storage: why is the reference sample decisive?

Under Art. 40/6 of the Regulation on Official Controls of Food and Feed, public and private institutions, workplaces that produce on site for mass consumption, and catering factories must keep a sample of each dish of every batch they produce for seventy-two hours under suitable conditions. The Ministry's official control procedure for foodborne illness requires these samples to be kept chilled or frozen.

If the sample storage arrangement works, the task at the time of an incident is simple: the samples from the meal in question and the previous meal are set aside, their labels are checked and they are kept for handing over to the official inspectors. If there are no samples, or samples were taken only of the main dish, it is often impossible to identify the source with certainty. Under Art. 41 of the same regulation, the cost of examining and analysing samples taken when poisoning is suspected is paid by the natural or legal persons responsible for the activity concerned. For the day-to-day arrangement for taking and storing samples, see our article on canteen and kitchen hygiene.

The role of the workplace physician

The workplace physician manages the medical side of the incident. The physician's duties are:

Assessing the workers who come in and deciding who will be observed and who will be referred,
Keeping the case list and making the comparison between those who ate and those who fell ill,
Ensuring the notification is made to the right body with the right information,
Asking whether kitchen staff have diarrhoea, vomiting or infected wounds on their hands, and ensuring that those with symptoms do not handle food until they have recovered,
Checking kitchen workers' carrier examination and hygiene training certificate records,
Assessing separately the return to work of workers who fell ill, especially workers who come into contact with the product in food manufacturing workplaces.

Catering company responsibility and the contract

In most workplaces, catering is bought in from a company. The catering company's responsibility has two sides. As a food business operator, under Art. 40 of the Regulation on Official Controls of Food and Feed the company must meet the requirements of the law at every stage of its activity, withdraw any product it considers unsafe and inform the Ministry's provincial or district directorate. From an OHS point of view, the company's workers work at your workplace; under Art. 23 of Law No. 6331 on Occupational Health and Safety, employers sharing the same work area cooperate and coordinate on OHS measures. For the relationship between the principal employer and the subcontractor, see our article on subcontractor OHS responsibility.

Including the following clauses explicitly in the contract prevents disputes when an incident occurs:

That a reference sample of every dish at every meal will be kept for 72 hours and the sample log shown to the employer,
That temperature records and ingredient supplier records will be kept,
That kitchen staff hygiene training and carrier examination records will be on file,
That the workplace physician may inspect the kitchen without notice,
That the company will be informed immediately if poisoning is suspected and will preserve its own records.

Work accident notification and after the incident

Art. 13 of Law No. 5510 includes events occurring while the insured person is at the workplace in the definition of a work accident. Workers who fall ill because of food eaten in the canteen are assessed from this perspective; events that qualify as work accidents are reported to the Social Security Institution (SGK) within 3 working days of the accident under Art. 14 of Law No. 6331. For the scope, see our article on what counts as a work accident, and for the steps of notification, see our article on SGK work accident e-notification.

Once the incident is closed, the root cause is identified, menu and preparation processes are reviewed and the outcome is taken to the OHS committee agenda. The Regulation on Emergencies in Workplaces lists poisoning and outbreaks caused by biological agents among the emergencies to be identified; writing a mass food poisoning scenario into the emergency plan ensures that the first hour is not lost in the next incident.

At Bursa Sistemer, through our workplace physician service, we regularly plan canteen inspections at businesses in Bursa and the surrounding provinces, monitor reference sample and staff health records, and run case tracking when poisoning is suspected. For food manufacturers, see our food sector page.

Frequently Asked Questions

How long is a reference sample kept?

Workplaces serving meals for mass consumption and catering factories keep a sample of each dish of every batch they produce for 72 hours under suitable conditions. Samples are kept chilled or frozen, in labelled, closed containers.

Does food poisoning count as a work accident?

If a worker fell ill because of food eaten in the canteen while at the workplace, the incident is assessed as a possible work accident. Events that qualify as work accidents are reported to SGK within 3 working days.

Who should we notify of suspected poisoning?

Suspected foodborne illness is reported to the provincial or district directorate of Agriculture and Forestry via the ALO 174 Food Line or by written application. The records of the healthcare facility assessing the sick workers support the notification.

Should the catering company be changed after a poisoning incident?

The decision should be based on identifying the source and on the company's corrective actions. Having reference sample, record-keeping and inspection clauses in the contract bases this assessment on concrete data.