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Applied and Environmental Microbiology, March 2001, p. 1300-1307, Vol. 67, No. 3
Department of Nutrition & Food Sciences,
Center for Microbe Detection & Physiology, Utah State University,
Logan, Utah 84322-8700
Received 10 March 2000/Accepted 7 December 2000
Current methods for the detection of pathogens in food and water
samples generally require a preenrichment step that allows selective
enrichment of the test organism. The objective of this research was to
eliminate an enrichment step to allow detection of bacteria directly in
food and water samples in 30 min. A high-flow-rate, fluidized bed to
capture and concentrate large (bacteria and spores) and small (protein)
molecules was developed. This format, ImmunoFlow, is volume independent
and uses large beads (greater than 3 mm in diameter) when capturing
bacteria to prevent sample clogging when testing food samples.
Detection of bound targets was done using existing enzyme-linked
immunosorbent assay (ELISA) protocols. Four antibodies
(anti-Escherichia coli O157:H7, -Bacillus
globigii, -bovine serum albumin [BSA], and -ovalbumin [OVA])
were covalently coupled to various glass and ceramic beads. Very
small amounts of BSA (<1 ng) and OVA (0.2 to 4.0 µg) were detected.
Various industrial and environmental samples were used to observe the effect of the sample composition on the capture of anti-B.
globigii and anti-E. coli O157:H7 modified beads. The
lower limit of detection for both E. coli O157:H7 and
B. globigii was 1 spore/cell independent of the sample
size. The activity of anti-B. globigii modified beads
declined after 3 days. Anti-E. coli O157:H7 modified beads declined in their capture ability after 2 days in various storage buffers. Storage temperature (4 and 25°C) did not influence the stability. The ImmunoFlow technology is capable of capturing bacteria and spores directly from samples, with subsequent detection in an ELISA
format in 30 min.
0099-2240/01/$04.00+0 DOI: 10.1128/AEM.67.3.1300-1307.2001
Solid-Phase Capture of Proteins, Spores, and
Bacteria


*
Corresponding author. Mailing address: Department of
Nutrition & Food Sciences, Center for Microbe Detection & Physiology, 8700 Old Main Hill, Utah State University, Logan, UT 84322-8700. Phone:
(435) 797-3356. Fax: (435) 797-0103. E-mail:
milkbugs{at}cc.usu.edu.
Approved as journal paper 7244 of the Utah Agricultural Experiment Station.
Present address: Weider Nutrition Int., Salt Lake City, Utah.
§
Present address: Kraft Foods, Glenview, Ill.
Present address: Bangs Laboratories, Fishers, Ind.
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