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Growth of Escherichia coli O157:H7 during sprouting of alfalfa seeds
Author(s) -
Stewart D.,
Reineke K.,
Ulaszek J.,
Fu T.,
Tortorello M.
Publication year - 2001
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2001.00957.x
Subject(s) - sprouting , biology , pathogen , escherichia coli , agar , inoculation , microbiology and biotechnology , bacteria , food science , horticulture , biochemistry , genetics , gene
Aims:Escherichia coli O157:H7 was monitored daily during sprouting of alfalfa seeds inoculated at high (3·92 log 10 cfu g –1 ) and low (1·86 log 10 cfu g –1 ) levels to assess the extent of pathogen growth during production. Methods and Results: Sprouts and rinse water were tested by direct and membrane filter plating on modified sorbitol MacConkey agar and BCM O157:H7(+) agar; the antibody‐direct epifluorescent filter technique; and rapid immunoassays. The pathogen reached maximum populations after one and two days of sprouting seeds inoculated at high and low levels, respectively; in either case, populations of 5–6 log 10 cfu g –1 were reached. Detection limits of two rapid immunoassays, Reveal and VIP, without enrichment were determined to be 5–7 log 10 cfu ml –1 . Conclusions: These results show the ability of E. coli O157:H7 to grow to high levels during sprouting; however, because these levels may be below detection limits, it is necessary to include enrichment when monitoring sprout production for E. coli O157:H7 by the rapid test kits. Significance and Impact of the Study: The data indicate that sprouts may harbor high levels of pathogens. The appropriate use of rapid test methods for pathogen monitoring during sprouting is indicated.