A multistate, foodborne outbreak of hepatitis A. National Hepatitis A Investigation Team. (1/33)

BACKGROUND: We investigated a large, foodborne outbreak of hepatitis A that occurred in February and March 1997 in Michigan and then extended the investigation to determine whether it was related to sporadic cases reported in other states among persons who had consumed frozen strawberries, the food suspected of causing the outbreak. METHODS: The cases of hepatitis A were serologically confirmed. Epidemiologic studies were conducted in the two states with sufficient numbers of cases, Michigan and Maine. Hepatitis A virus RNA detected in clinical specimens was sequenced to determine the relatedness of the virus from outbreak-related cases and other cases. RESULTS: A total of 213 cases of hepatitis A were reported from 23 schools in Michigan and 29 cases from 13 schools in Maine, with the median rate of attack ranging from 0.2 to 14 percent. Hepatitis A was associated with the consumption of frozen strawberries in a case-control study (odds ratio for the disease, 8.3; 95 percent confidence interval, 2.1 to 33) and a cohort study (relative risk of infection, 7.5; 95 percent confidence interval, 1.1 to 53) in Michigan and in a case-control study in Maine (odds ratio for infection, 3.4; 95 percent confidence interval, 1.0 to 14). The genetic sequences of viruses from 126 patients in Michigan and Maine were identical to one another and to those from 5 patients in Wisconsin and 7 patients in Arizona, all of whom attended schools where frozen strawberries from the same processor had been served, and to those in 2 patients from Louisiana, both of whom had consumed commercially prepared products containing frozen strawberries from the same processor. CONCLUSIONS: We describe a large outbreak of hepatitis A in Michigan that was associated with the consumption of frozen strawberries. We found apparently sporadic cases in other states that could be linked to the same source by viral genetic analysis.  (+info)

An outbreak of calicivirus associated with consumption of frozen raspberries. (2/33)

In April 1988, an outbreak of gastroenteritis occurred among employees in a large company in Helsinki, Finland. A retrospective cohort study, using a self-administered questionnaire, was carried out to ascertain the cause and extent of the outbreak. To meet the case definition, employees had to have had diarrhoea and/or vomiting since 2 April, 1998. A subanalysis was made in the biggest office, consisting of 360 employees, of whom 204 (57%) completed the questionnaire. Of these 108 (53%) met the case definition. Employees who had eaten raspberry dressing were more likely to meet the case definition than those who had not (Attack Rate (AR) 65% versus AR 18% Relative Risk, (RR) 3.7, 95%, Confidence Intervals (CI) 2.0-6.7). Four stool specimens obtained from affected kitchen staff who had all eaten the raspberry dressing and who had all become ill simultaneously with the employees were positive by polymerase chain reaction (PCR) for calicivirus. The data suggest that the primary source of the outbreak was imported frozen raspberries contaminated by calicivirus.  (+info)

Detection of Salmonella by using the colorimetric DNA/rRNA sandwich hybridization in microtiter wells. (3/33)

A rapid and readily available DNA probe kit was developed for the detection of Salmonella spp. This kit utilized the colorimetric DNA/rRNA sandwich hybridization method in microtiter wells. Within 3 hr Salmonella spp. in selective enrichment broth cultures were detected by the DNA probe kit. The kit effectively identified all of 187 strains of Salmonella tested and yielded no false-positive reactions in the examination of 674 pure cultures of non-salmonellae. The DNA probe kit could detect 10(5) cfu/ml in pure culture. A total of 379 naturally contaminated samples (raw chicken meat, liquid egg, animal feeds, poultry feces and frozen foods) were tested, both by the standard culture method and the DNA probe kit. The 169 of these samples were culture positive and 210 were culture negative. The sensitivity of the DNA probe kit was 98.2% (166/169) and the specificity was 99.5% (209/210). These results show that the DNA probe kit is a useful tool to examine a large number of various samples for contamination by Salmonella spp. in food and livestock industry.  (+info)

Isolation of mycobacteria from frozen fish destined for human consumption. (4/33)

Mycobacteria were isolated from defrost water and tissue of sole (Solea solea), hake (Merluccius merluccius), cod (Gadus morhua), ling (Genypterus blacodes), and monkfish (Lophius piscatorius) on Lowenstein-Jensen medium after incubation at different temperatures. Samples of frozen fish were obtained under sterile conditions inside a refrigeration chamber (-18 to -22 degrees C) in a wholesale market from which these products are distributed to shops for retail sale and human consumption.  (+info)

Repair and enumeration of injured coliforms by a plating procedure. (5/33)

Surface plating of coliforms on Trypticase soy agar, followed by 1 to 2 h of incubation at 25 C and subsequent overlay with violet red bile agar, was found to be a useful method for the repair and enumeration of coliforms injured by freezing.  (+info)

Studies on the estimation of the hygienic condition of frozen broiler chickens. (6/33)

Various sampling techniques to determine the aerobic, E. coli and Enterobacteriaceae counts and to detect the presence of salmonellas were compared. As a simple method for the detection of salmonellas a modified Surkeiwicz procedure using both drip and rinse water is advocated. To evaluate hygiene during processing, determination of the number of Enterobacteriaceae in pieces of skin from the ventral, lateral and breast region is preferred.  (+info)

Lethal ingestion of stored Amanita phalloides mushrooms. (7/33)

We report the first case of a lethal Amanita phalloides intoxication from stored mushrooms. After picking the mushrooms were kept in a freezer for 7-8 months. This case is in accordance with the well-known stability of the amatoxins and demonstrates the possibility of A. phalloides poisoning at any time of year.  (+info)

An outbreak of typhoid Fever in Florida associated with an imported frozen fruit. (8/33)

An outbreak of typhoid fever in Florida involving at least 16 persons during the winter of 1998-99 was investigated using case-control, environmental, and laboratory methods. The genomic profiles of Salmonella serovar Typhi (Salmonella Typhi) isolates from the 15 confirmed case subjects were identical. Consumption of fruit shakes made with frozen mamey, a tropical fruit, was significantly associated with illness (matched odds ratio, 7.6; 95% confidence interval, 1.4-81.4). Laboratory testing showed that the fruit was heavily contaminated with fecal coliforms; no Salmonella Typhi was isolated. The frozen mamey was prepared in plants in Guatemala and Honduras. No further cases occurred after the frozen product was recalled. As our nation's food sources become increasingly globalized, the risk of outbreaks of exotic diseases linked to contaminated imported food will increase. This outbreak highlights the need for new approaches to ensure the safety of our food supply.  (+info)