Salmonella is a leading cause of foodborne outbreaks in Taiwan. On 27 April 2018, a salmonellosis outbreak among customers of a restaurant was reported to the Taiwan CDC. We investigated the outbreak to identify infection sources and prevent further transmission. We interviewed ill customers and their dining companions. We conducted a case-control study to identify foods associated with the illness. Case-patients were those who had diarrhoea within 72 h after eating at the restaurant during 16–27 April 2018. Specimens, food samples and environmental samples were collected and tested for enteric pathogens. Salmonella isolates were analysed with pulse-field gel electrophoresis and whole-genome sequencing. We inspected the restaurant sanitation and reviewed kitchen surveillance camera recordings. We identified 47 case-patients, including one decedent. Compared with 44 controls, case-patients were more likely to have had a French toast sandwich (OR: 102.4; 95% CI: 18.7–952.3). Salmonella Enteritidis isolates from 16 case-patients shared an indistinguishable genotype. Camera recordings revealed eggshell contamination, long holding time at room temperature and use of leftovers during implicated food preparation. Recommendations for restaurant egg-containing food preparation are to use pasteurised egg products and ensure a high enough cooking temperature and long enough cooking time to prevent Salmonella contamination.

An acute gastroenteritis (AGE) outbreak was reported in May 2013 in Gyeonggi Province, South Korea. Eight students who had eaten breakfast on 21 May 2013 at a high-school restaurant exhibited AGE symptoms. Our case-control study showed that a strong association was observed between AGE symptoms and fermented oyster consumption. Virological studies also indicated that noroviruses (NoVs) were detected from both clinical samples and fermented oyster samples, and multiple different genotypes (genogroups GII.4, GII.11 and GII.14) of NoVs were present in both samples. The nucleotide sequence similarity between the strains found in the clinical samples and those in the fermented oysters was more than 99·5%. Therefore, to prevent further outbreaks, proper management of raw oysters is necessary and the food industry should be aware of the risk of viral gastroenteritis posed by fermented oysters contaminated with NoVs.

During one week in July 2012, two patients from the same ward at the municipal hospital in Vaasa, Finland, were diagnosed with septicaemia caused by Listeria monocytogenes. An outbreak investigation revealed eight concomitant cases of febrile gastroenteritis caused by L. monocytogenes on the same ward. Median age of the cases was 82 years and median incubation time for listerial gastroenteritis was 21 h (range 9–107). An additional 10 cases of invasive listeriosis caused by the same outbreak strain were identified across the whole country during the summer of 2012. Environmental investigation at the affected municipal hospital ward revealed ready-sliced meat jelly as the suspected source of the infection. During inspection of the meat jelly production plant, one pooled sample taken from a floor drain and a trolley wheel in the food processing environment was positive for the outbreak strain of L. monocytogenes. After the producer stopped the production of meat jelly, no further cases of listeriosis with the outbreak strain were identified via nationwide surveillance.

Botulism is a severe neuroparalytic disorder that can be potentially life-threatening. In Barcelona, Spain, no outbreaks had been reported in the past 25 years. However, in September 2011, two outbreaks occurred involving two different families. A rare case of Clostridium baratii which produced a neurotoxin F outbreak was detected in five family members who had shared lunch, and several days before that another family was affected by C. botulinum toxin A which was probably present in homemade pâté.

An outbreak of gastroenteritis affected at least 240 persons who had eaten at a gourmet restaurant over a period of 7 weeks in 2009 in England. Epidemiological, microbiological, and environmental studies were conducted. The case-control study demonstrated increased risk of illness in those who ate from a special ‘tasting menu’ and in particular an oyster, passion fruit jelly and lavender dish (odds ratio 7·0, 95% confidence interval 1·1–45·2). Ten diners and six staff members had laboratory-confirmed norovirus infection. Diners were infected with multiple norovirus strains belonging to genogroups I and II, a pattern characteristic of molluscan shellfish-associated outbreaks. The ongoing risk from dining at the restaurant may have been due to persistent contamination of the oyster supply alone or in combination with further spread via infected food handlers or the restaurant environment. Delayed notification of the outbreak to public health authorities may have contributed to outbreak size and duration.

Despite the frequency of Campylobacter as the principal cause of bacterial gastroenteritis in the UK, outbreaks attributed to this pathogen are rare. One hundred and fourteen general foodborne outbreaks of campylobacteriosis were reported to the Health Protection Agency from 1992 to 2009 with most occurring in food service establishments (64%, 73/114). Poultry meat (38%, 43/114) was the most commonly reported vehicle of infection, of which poultry liver pâté, and undercooking, were strongly associated with this pathogen. Notably, the number of outbreaks of campylobacteriosis linked to consumption of poultry liver pâté in England and Wales increased significantly from 2007 (74% as opposed to 12%, P<0·00001) with a preponderance of these occurring in December. These outbreaks highlight the hazards associated with inappropriate culinary practices leading to undercooking of poultry liver pâté and suggest that improving catering practice is an important last line of defence in reducing exposure to Campylobacter-contaminated products.

Over 400 office workers from the same unit of a manufacturing company in Stockholm County, Sweden, fell ill with gastroenteritis. A retrospective cohort study of office workers in the affected unit demonstrated that canteen visitors on one day had an increased risk of illness [risk ratio (RR) 27·1, 95% confidence interval (CI) 15·7–46·8] compared to non-visitors. A second study, investigating canteen visitors' consumption of particular food items, showed that both tomatoes from the salad buffet (RR 5·6, 95% CI 3·2–9·6) and hamburgers (RR 4·9, 95% CI 2·4–9·8) were the most likely vehicles of infection. Norovirus GI.3 (Desert Shield) was identified in stool samples from three office workers and from a food handler who prepared the tomatoes for the salad buffet and hamburger ingredients before vomiting at the workplace on 12 November. The outbreak could have been prevented if the food items prepared by the food handler some hours before vomiting had not been served.

Foodborne outbreaks of cryptosporidiosis are uncommon. In Denmark human cases are generally infrequently diagnosed. In 2005 an outbreak of diarrhoea affected company employees near Copenhagen. In all 99 employees were reported ill; 13 were positive for Cryptosporidium hominis infection. Two analytical epidemiological studies were performed; an initial case-control study followed by a cohort study using an electronic questionnaire. Disease was associated with eating from the canteen salad bar on one, possibly two, specific weekdays [relative risk 4·1, 95% confidence interval (CI) 2·1–8·3]. Three separate salad bar ingredients were found to be likely sources: peeled whole carrots served in a bowl of water, grated carrots, and red peppers (in multivariate analysis, whole carrots: OR 2·1, 95% CI 1·1–4·0; grated carrots: OR 2·1, 95% CI 1·2–3·9; peppers: OR 3·3, 95% CI 1·7–6·6). We speculate that a person excreting the parasite may have contaminated the salad buffet.

Vibrio parahaemolyticus and Norovirus have been recognized as the cause of sporadic cases or outbreaks of diarrhoeal illness in association with the ingestion of raw or improperly cooked seafood. This report describes a foodborne outbreak of gastroenteritis caused by both Norovirus and Vibrio parahaemolyticus following the consumption of raw seafood in a restaurant in Terrassa (Catalonia, Spain) in September 2005. Measures are needed to reduce contamination of raw seafood. Consumers can reduce the risk of foodborne illness by avoiding consumption of raw or undercooked food.