Title: Hafnia, the genus Authors
Submitted to: Encyclopedia of Food Microbiology
Publication Type: Book / Chapter
Publication Acceptance Date: December 1, 2013
Publication Date: April 23, 2014
Citation: Smith, J.L. 2014. Hafnia, the genus. In: Batt, C.A., Tortorello, M.L.(Eds.), Encyclopedia of Food Microbiology. Vol 2. Elsevier Ltd, Academic Press, p. 117-120. Technical Abstract: The Hafnia species, H. alvei and H. paralvei, are Gram-negative rods belonging to the family Enterobacteriaceae. The organisms grow at temperatures between 4 deg and 44 deg C and are facultatively anaerobic. They are found in the environment (soil, water, sewage), gastrointestinal tract of animals and humans, and foods. Hafnia species are minor pathogens for humans and act as rare opportunistic pathogens of immunocompromised individuals such as the elderly, very young, and very ill. The major symptom of infection is bacteremia. A few virulence mechanisms have been shown for Hafnia including the production of fimbriae and endotoxin, cell invasion, biofilm formation, and resistance to killing by human serum. The status of the organism as a foodborne gastrointestinal pathogen is controversial and has not been authentically documented. Furthermore, Hafnia species have characteristics that could induce spoilage in foods (production of biofilms, histamine, and gas) but the organisms are part of the mixed microflora of raw and processed foods and their role in food spoilage is uncertain.