title: Food-borne nitrates and nitrites as a cause of methemoglobinemia.
abstract: Methemoglobinemia is a potentially fatal condition. Previous reports of toxic methemoglobinemia due to food-borne nitrates and nitrites are reviewed. Contamination of food during manufacture or degradation of nitrates in vegetables appear to be the most important factors. Some food items, such as refrigerated "dim-sum", stuffed pork and Chinese sausages, are very popular among some Asian populations; a stringent control against the excessive use of nitrates and nitrites is required in order to prevent outbreaks of toxic methemoglobinemia. Patients with glucose-6-phosphate dehydrogenase deficiency, a common condition in some Asian populations, may present with methemoglobinemia and intravascular hemolysis following exposure to oxidant drugs or chemicals. Methylene blue is inefficient and may exacerbate hemolysis in these patients; partial exchange transfusion may be required.
authors.affiliation: Department of Clinical Pharmacology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
authors.forename: T Y
authors.initials: TY
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling; D005519:Food Preservation; D005517:Foodborne Diseases / Q000209:etiology; D006723:Hong Kong; D006801:Humans; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced*; D008875:Middle Aged; D009566:Nitrates / Q000009:adverse effects* / Q000032:analysis; D009573:Nitrites / Q000009:adverse effects* / Q000032:analysis
chemical_list: D009566:Nitrates; D009573:Nitrites