Safety risks associated with dispersal of E. coli O157:H7 in home sprouting modules

Seed Disinfestation Practices to Control Seed-Borne Fungi and Bacteria in Home Production of Sprouts

Concern over microbial contamination limits the adoption of home production of sprouts as a nutritious and sustainable food. Simple, accessible approaches to seed disinfection could support safe home seed sprouting. Here, we quantify bacterial and fungal contamination of seeds of 14 plant cultivars sold for home sprout production and test a range of chemical and physical methods for seed disinfestation appropriate for home use. Most seeds are contaminated with a variety of bacteria and fungi, and those microbes are usually limited to the seed surface. Heat treatments are not effective for seed disinfection because the high temperatures needed to effectively reduce microbial contamination also reduce seed germination. Two chlorine-based chemical disinfectants-dilute household bleach (0.6% sodium hypochlorite) and freshly generated hypochlorous acid (800 ppm chlorine)-were the most effective disinfection agents tested (up to a 5-log reduction in bacteria) that also did not harm seed germination.

Rapid and highly sensitive detection of Escherichia coli O157:H7 in food with loop-mediated isothermal amplification coupled to a new bioluminescent assay

Testing for bioluminescent pyrophosphate is a convenient method of DNA detection without complex equipments, but it is insufficiently sensitive and offers no particular time advantage over other rapid detection methods. The shortcomings of the traditional bioluminescent pyrophosphate method have been addressed by using 2-deoxyadenosine-5-(α-thio)-triphosphate (dATPαS) instead of dATP for LAMP, thus reducing the high background signal and generating a constant background value. In this study, LAMP coupled to a novel bioluminescent pyrophosphate assay was developed to detect E. coli O157:H7. The new method has a limit of detection of <10 copies/μL or 5 CFU/mL; its sensitivity is higher than that of the conventional LAMP assay. Moreover, a food-borne pathogen can be detected when a single DNA template is included in the LAMP assay, making it 100 times more sensitive than the traditional LAMP method. Three hundred food samples were tested with this assay and the accuracy of detection was verified with a culture method and MALDI Biotyper. The assay only took 90-120 min and detected <10 copies of the pathogen. This method had the advantages of rapidity, sensitivity, and simplicity, so it is very competitive for the rapid and highly sensitive detection of food-borne pathogens.