In collaboration with the Environmental Health Services of Hyvinkää City, the Central Uusimaa Environmental Center, and the Environmental Health Services of Vantaa City, Helsinki City's Environmental Services conducted a study between 2022 and 2023 to assess the microbiological quality of hamburger or sandwich fillings in fast-food restaurants and the cleanliness of restaurant surfaces.
A total of 42 raw hamburger patties and 143 samples of chopped vegetables were collected for analysis, with an additional 14 re-samples taken due to poor results. The samples were examined for spoilage bacteria and disease-causing bacteria. In addition, 282 samples were taken from kitchen surfaces for microbiological examinations to assess the cleanliness of kitchen equipment and furniture, with 14 re-samples taken for the same reason.
The majority of vegetables arrive at restaurants pre-chopped, with their quality affected mainly by storage temperature and shelf life. According to the results, vegetable storage temperatures are appropriate, and the vegetables are used promptly after opening the packaging. Of the samples of chopped vegetables, 67% were of good microbiological quality, 29% were acceptable, and 4% were poor. Sensory evaluations of the vegetable samples did not reveal any issues, and disease-causing bacteria were not detected.
Regarding the hamburger patties, 69% were found to be of good microbiological quality, 24% were acceptable, and 7% were poor. Disease-causing Salmonella bacteria were detected in two samples, and STEC (Shiga toxin-producing Escherichia coli) bacteria were found in 11 samples. All findings of Salmonella and STEC were traced back to patties of foreign origin.
Salmonella and STEC bacteria originate from the intestines of animals and usually contaminate meat during the slaughtering process. Both Salmonella and STEC bacteria are destroyed when patties are cooked thoroughly. These bacteria can cause food poisoning in humans, with symptoms ranging from mild diarrhea to severe conditions such as bloody diarrhea and hemolytic-uremic syndrome (HUS), which can lead to kidney failure in severe cases. There are over 2,000 types of Salmonella, and all of them can potentially cause illness in humans. The most common symptoms of intestinal Salmonella infection are diarrhea and fever.
The study also indicated that the cleanliness of equipment and furniture in fast-food restaurants was generally at a high level. Only four percent of the samples showed poor surface cleanliness.
Hygiene in fast-food restaurants is regularly inspected during routine visits. The inspection results are publicly available on the www.oivahymy.fi website.
This collaborative study underscores the commitment of the Helsinki City's Environmental Services and its partner municipalities to ensure the safety and quality of food served in fast-food establishments, providing reassurance to consumers about the hygiene and microbiological standards in these popular dining venues.