Diagnosis of botulism in two teenaged sisters in Montreal led to the identification of 36 previously unrecognized cases of type B botulism in persons who had eaten at a restaurant in Vancouver, British Columbia, during the preceding 6 weeks. A case-control study implicated a new vehicle for botulism, commercial chopped garlic in soybean oil (P less than 10(-4)). Relatively mild and slowly progressive illness, dispersion of patients over at least eight provinces and states in three countries, and a previously unsuspected vehicle had contributed to prolonged misdiagnoses, including myasthenia gravis (six patients), psychiatric disorders (four), stroke (three), and others. Ethnic background influenced severity of illness: 60% of Chinese patients but only 4% of others needed mechanical ventilation (P less than 10(-3]. Trypsinization of serum was needed to show toxemia in one patient. Electromyography results with high-frequency repetitive stimulation corroborated the diagnosis of botulism up to 2 months after onset. Although botulism is a life-threatening disease, misdiagnosis may be common and large outbreaks can escape recognition completely.

Twenty-nine confirmed cases of Salmonella nima enterocolitis in Canada and four cases in the United States were traced to gold-foil wrapped chocolate coins from Belgium. Illness in Canadian cases occurred between September 1985 and October 1986 where the primary case in each of 24 affected families was a child ≤ 14 years of age. A product recall was issued on October 3, 1986 in Canada. Quantitative analysis of four composite samples of suspect chocolate by the most probable number (MPN) technique showed levels of 4.3 to 24.0 S. nima per 100 g product. These levels of contamination and consumption of approximately 25 g of chocolate by primary cases suggest that small numbers of S. nima precipitated clinical symptoms.

No abstract

Microbiological standards are proposed for ground beef sold in Canada. The proposal is based on a national survey conducted in 1974–75. The proposed standards are: aerobic colony count (35 C), ⩽ 107 for non-frozen and ⩽106 for frozen products; Escherichia coli, ⩽102; Staphylococcus aureus, ⩽102 per g; and Salmonella, absent in 25-g portions from each of five subsamples. To accomodate the variable distribution of bacteria between packages in a single lot of product, three-class plan based on a format suggested by the International Commission on Microbiological Specifications for Foods is used.

Refrigeration (4 C) of non-selective and selective enrichment broth cultures for 72 h did not markedly affect detection of Salmonella in 160 contaminated high and low moisture foods. Detection in refrigerated preenrichment (non-selective) broth cultures of poultry and high and low moisture foods was 90, 95 and 100%, respectively; homologous results for refrigerated selective enrichment broth cultures were 90, 100 and 100%. All but one of the 22 negative results were obtained with poultry and two of the six laboratories participating in poultry analysis contributed 19 of the 21 negative results. Refrigeration of broth cultures provides greater operational flexibility by increasing the number of days on which analyses can be initiated without engendering work outside a normal work week.