Berries - Advice to boil imported frozen berries
Why does the FSAI advise that imported frozen berries should be boiled for one minute?
As a result of outbreaks of norovirus and hepatitis A virus in imported frozen berries across Europe in recent years, the FSAI recommends boiling imported frozen berries for one minute before consumption. This is particularly important when serving these foods to vulnerable people such as nursing home residents.
When did FSAI first issue this advice?
The FSAI first issued this advice in 2013, during the investigation of an outbreak of hepatitis A virus in Ireland which was linked to imported frozen berries. The outbreak turned out to be part of a multi-state outbreak, with over 1,000 cases reported in 12 EU countries.
Is there evidence that the risk still exists?
Between 2014 and 2022 (to date, 12th August), there have been 6 alerts
issued across Europe for hepatitis A virus and 45 alerts for norovirus in imported
In 2015, an outbreak of norovirus occurred in a Swedish nursing home causing 70 people to become ill. Three deaths were reported to have been potentially linked to this outbreak. Microbiological analysis confirmed the presence of norovirus in the frozen berries. In June 2018, an outbreak of hepatitis A virus in Sweden was linked to frozen strawberries from a Polish based processing plant. People became ill after eating smoothies or a dessert containing frozen imported strawberries that were not boiled before consumption. The same type of hepatitis A virus (genotype 1B) that caused the illness was found in a batch of frozen strawberries from the implicated processing plant.
How do I know if frozen berries are imported?
If the label does not state the country of origin, you should assume that the berries are imported. The shop where you purchased the berries may be able to provide this information.
Will retailers be displaying notices about the requirement to boil imported frozen berries?
Retailers selling imported frozen berries need to ensure that the berries they use are sourced from reputable suppliers operating effective food safety management systems and comprehensive traceability systems. As the food chain can be quite complex, it is necessary for food businesses at each stage of the food chain to seek assurances regarding the effectiveness of the food safety management systems in place from their suppliers. If such assurances are not available, the FSAI recommends that the retailer displays a notice advising customers that the frozen berries should be boiled for one minute before consumption.
How do I know that the berries used by food businesses (e.g. smoothie bars, cake manufacturers, etc.) are safe to eat?
Food businesses using imported frozen berries need to ensure that the berries they use are sourced from reputable suppliers operating effective food safety management systems and comprehensive traceability systems. As the food chain can be quite complex, it is necessary for food businesses at each stage of the food chain to seek assurances regarding the effectiveness of the food safety management systems in place from their suppliers. If such assurances are not available, the FSAI recommends that the berries should be boiled for one minute before being used in foods. If you are concerned about where the berries have come from, ask the food business and they will also be able to advise whether the berries were boiled.
What if I have some berries in my freezer at home – are these safe to eat?
If the berries are imported we recommend that you boil them for one minute before consumption. Boiling for one minute will destroy viruses, if present.
Are fresh berries safe/ok to eat?
There is no evidence to suggest that fresh Irish or fresh imported berries are a risk. Fresh berries should be washed before consumption which is in keeping with the advice for all fresh fruit and vegetables.
Can I eat the berries I grow in my own garden?
Yes, this issue only relates to frozen imported berries and so this advice does not apply to berries grown in your own garden and frozen after picking.
Why are imported frozen berries more of a risk than other types of berries?
Across Europe, more outbreaks have been linked to imported frozen berries than to other types of berries. Freezing preserves viruses such as norovirus and hepatitis A.
Are tinned berries also a risk?
No, tinned or canned berries have not been identified as a risk.
What if I have eaten frozen berries recently, without boiling them?
The time from consumption of contaminated food to the onset of illness with hepatitis A, ranges from 15-50 days, with the average being 28 days. In the case of norovirus, symptoms usually appear around 12 to 48 hours after consuming contaminated food.
If you think that you may be ill as a result of having consumed frozen berries, you should seek medical advice. This applies in all cases if you believe that any food you have eaten has made you ill.
Should I stop buying frozen berries?
No, there is no need to stop buying frozen berries. You can ensure that the berries are safe to eat by boiling for one minute.
I have given my toddler/child puree made from frozen berries, should I be worried?
If you are concerned about your toddler/child, you should seek medical advice but you should not be concerned about giving them berries that have been boiled. Boiling for one minute will destroy viruses, if present.
What is hepatitis A and what are the symptoms?
Hepatitis A infection is an acute disease of the liver caused by the hepatitis A virus. There are five main hepatitis viruses, referred to as types A, B, C, D and E.
Illness usually starts about 28 days after exposure to the virus, but it can start anytime between 15 and 50 days after infection. The most common symptoms are fever, loss of appetite, nausea, fatigue and abdominal pain, followed within a few days by jaundice. The disease often fails to show the noticeable symptoms or is mild, particularly in children below five years. Jaundice occurs in 70-80% of people aged over 14 years and less than 10% of children younger than six years. Symptoms may last from one or two weeks to a number of months. Prolonged, relapsing hepatitis for up to one year occurs in 15% of cases.
What should I do if I think I have hepatitis A?
You should seek medical advice. More information on hepatitis A can be found on the Health Protection Surveillance Centre (HPSC) website.
How is hepatitis A virus spread?
Hepatitis A is a human virus that is primarily spread from person-to-person via the faecal-oral route. The virus is shed in the faeces of infected people. It may also be spread through food that has been contaminated by infected food handlers or by contaminated water. People who have the virus are most infectious in the week or two before onset of symptoms and may be infectious up to one week after onset.
What is norovirus and what are the symptoms?
Norovirus is one of the most common causes of gastroenteritis. Symptoms include - nausea (often sudden onset), vomiting (often projectile) and watery diarrhoea. Symptoms begin around 12 to 48 hours after becoming infected. The illness is usually brief, with symptoms lasting only about 1 or 2 days. Most people make a full recovery within 1-2 days, however some people (usually the very young or elderly) may become very dehydrated and require hospital treatment.
What should I do if I think I have norovirus?
You should seek medical advice. More information on norovirus can be found on the Health Protection Surveillance Centre (HPSC) website.
How is norovirus spread?
Noroviruses are very contagious and can spread easily from person-to-person. Both the faeces and vomit of an infected person contain the virus and are infectious. People infected with norovirus are contagious from the moment they begin feeling ill to 2/3 days after recovery. Some people may be contagious for as long as 2 weeks after recovery.
It is important for people to use good handwashing and other hygienic practices after they have recently recovered from norovirus illness. In addition, noroviruses are very resilient and can survive in the environment (e.g. on surfaces) for a number of weeks.
How might berries become contaminated with norovirus and hepatitis A virus?
Contamination could occur on the farm, through use of sewage-contaminated agricultural water or through contamination by infected workers. Cross-contamination could occur post-harvest along the supply chain, through contact with contaminated surfaces of machines, equipment and facilities during freezing, mixing and packaging processes.
What was the source of contamination of the frozen berries in the 2013 hepatitis A virus outbreak?
The multi-state investigation did not identify the source of the contamination. The investigation concluded that contamination could have occurred at the freezing processor or at the primary production stage. It highlighted the importance of compliance with Good Hygiene Practice (GHP) and Good Agricultural Practice (GAP) and cautioned that contaminated product related to the outbreak could still be circulating in the food chain.
Read investigation report.
What was the evidence that linked imported frozen berries with the 2013 multi-state hepatitis A virus outbreak in Europe?
Contaminated batches of mixed frozen berries/berry-containing products were identified in Italy, France and Norway were recalled from the market. This evidence together with epidemiological and environmental investigations from the affected countries identified frozen berries as the mostly likely vehicle of infection for this outbreak and suggested that it could be a single outbreak linked to a common, continuous source of contamination.
At the request of the European Commission, the European Food Safety Authority (EFSA) coordinated the tracing activities of affected Member States. This work involved collecting data on the source of each berry delivery from retail sale back to the farmer to see if a common source or sources of contamination could be identified. Bulgarian blackberries and Polish redcurrants were identified as the most common ingredient in the food consumed by affected people. However, this might be explained by the fact that Poland is the largest producer of redcurrants in Europe, and Bulgaria is a major exporter of frozen blackberries. While no single point source of contamination was identified, twelve food operators were identified with links to cases and batches in five of the countries affected.
Last reviewed: 16/8/2022