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Detection of shiga toxins by lateral flow assay.

Ching KH, He X, Stanker LH, Lin AV, McGarvey JA, Hnasko R - Toxins (Basel) (2015)

Bottom Line: The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk.This LFA provides a rapid and sensitive test for the detection of Stxs directly from STEC culture supernatants or at risk food samples with a 0.1 ng/mL limit of detection (LOD) for Stx2a.This Stx LFA is applicable for use in the rapid evaluation of Stx production from cultured E. coli strains or as a tool to augment current methods as part of food safety testing.

View Article: PubMed Central - PubMed

Affiliation: Produce Safety & Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan St, Albany, CA 94710, USA. kathryn.ching@ars.usda.gov.

ABSTRACT
Shiga toxin-producing Escherichia coli (STEC) produce shiga toxins (Stxs) that can cause human disease and death. The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk. In this manuscript, we report the development of a colorimetric lateral flow assay (LFA) for the rapid detection of Stxs in <10 min using a pair of monoclonal antibodies that bind epitopes common to Stx1 and six Stx2 variants. This LFA provides a rapid and sensitive test for the detection of Stxs directly from STEC culture supernatants or at risk food samples with a 0.1 ng/mL limit of detection (LOD) for Stx2a. This Stx LFA is applicable for use in the rapid evaluation of Stx production from cultured E. coli strains or as a tool to augment current methods as part of food safety testing.

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Related in: MedlinePlus

Detection of Stx2a from spiked lettuce samples by LFA. Lettuce samples were chopped, suspended in PBS and spiked with purified Stx2a (100–1 ng/mL). Samples were then mixed, centrifuged and the resulting supernatants evaluated for Stx2a detection using the LFA. T, test line; C, control line; +, positive test result; −, negative test result.
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toxins-07-01163-f004: Detection of Stx2a from spiked lettuce samples by LFA. Lettuce samples were chopped, suspended in PBS and spiked with purified Stx2a (100–1 ng/mL). Samples were then mixed, centrifuged and the resulting supernatants evaluated for Stx2a detection using the LFA. T, test line; C, control line; +, positive test result; −, negative test result.

Mentions: Leafy greens can become contaminated with STEC during growth or harvest, as fields are typically fertilized with manure or inadvertently exposed to water runoff contaminated with feces, both potential reservoirs of STEC bacteria [28,29]. Samples of lettuce (0.1 g) were chopped, placed in 1 mL of PBS and spiked with four concentrations of purified Stx2a (100–1 ng/mL). Spiked samples were vortexed, then centrifuged for 15 min at 12,000× g at 4 °C to remove solids and the supernatant tested by LFA (Figure 4). The lateral flow rate of lettuce supernatants was equivalent to buffer with the LFA resolving in 1 min at an LOD of 1 ng/mL.


Detection of shiga toxins by lateral flow assay.

Ching KH, He X, Stanker LH, Lin AV, McGarvey JA, Hnasko R - Toxins (Basel) (2015)

Detection of Stx2a from spiked lettuce samples by LFA. Lettuce samples were chopped, suspended in PBS and spiked with purified Stx2a (100–1 ng/mL). Samples were then mixed, centrifuged and the resulting supernatants evaluated for Stx2a detection using the LFA. T, test line; C, control line; +, positive test result; −, negative test result.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4417961&req=5

toxins-07-01163-f004: Detection of Stx2a from spiked lettuce samples by LFA. Lettuce samples were chopped, suspended in PBS and spiked with purified Stx2a (100–1 ng/mL). Samples were then mixed, centrifuged and the resulting supernatants evaluated for Stx2a detection using the LFA. T, test line; C, control line; +, positive test result; −, negative test result.
Mentions: Leafy greens can become contaminated with STEC during growth or harvest, as fields are typically fertilized with manure or inadvertently exposed to water runoff contaminated with feces, both potential reservoirs of STEC bacteria [28,29]. Samples of lettuce (0.1 g) were chopped, placed in 1 mL of PBS and spiked with four concentrations of purified Stx2a (100–1 ng/mL). Spiked samples were vortexed, then centrifuged for 15 min at 12,000× g at 4 °C to remove solids and the supernatant tested by LFA (Figure 4). The lateral flow rate of lettuce supernatants was equivalent to buffer with the LFA resolving in 1 min at an LOD of 1 ng/mL.

Bottom Line: The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk.This LFA provides a rapid and sensitive test for the detection of Stxs directly from STEC culture supernatants or at risk food samples with a 0.1 ng/mL limit of detection (LOD) for Stx2a.This Stx LFA is applicable for use in the rapid evaluation of Stx production from cultured E. coli strains or as a tool to augment current methods as part of food safety testing.

View Article: PubMed Central - PubMed

Affiliation: Produce Safety & Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan St, Albany, CA 94710, USA. kathryn.ching@ars.usda.gov.

ABSTRACT
Shiga toxin-producing Escherichia coli (STEC) produce shiga toxins (Stxs) that can cause human disease and death. The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk. In this manuscript, we report the development of a colorimetric lateral flow assay (LFA) for the rapid detection of Stxs in <10 min using a pair of monoclonal antibodies that bind epitopes common to Stx1 and six Stx2 variants. This LFA provides a rapid and sensitive test for the detection of Stxs directly from STEC culture supernatants or at risk food samples with a 0.1 ng/mL limit of detection (LOD) for Stx2a. This Stx LFA is applicable for use in the rapid evaluation of Stx production from cultured E. coli strains or as a tool to augment current methods as part of food safety testing.

Show MeSH
Related in: MedlinePlus