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Attachment and Biofilm Formation by Selected Strains of Salmonella enterica and Entrohemorrhagic Escherichia coli of Fresh Produce Origin
Author(s) -
Han Ran,
Klu Yaa Asantewaa Kafui,
Chen Jinru
Publication year - 2017
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.13722
Subject(s) - salmonella enterica , biofilm , salmonella , escherichia coli , microbiology and biotechnology , incubation , crystal violet , bacteria , biology , chemistry , food science , biochemistry , gene , genetics
This study compared the abilities of selected Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) strains of fresh produce origin to form biofilms on polystyrene surface and to attach to alfalfa and bean sprouts. Each of the 7 S. enterica and 4 EHEC inocula (2 mL; 10 7 CFU/mL) was placed in 6 different broths in 24‐well polystyrene tissue culture plates at 28 °C for 1 to 7 d. Developed biofilms were quantified using the crystal violet binding assay. In a separate experiment, alfalfa and mung bean sprouts (5 g) were exposed to 25 mL inocula (10 7 CFU/mL) of S. enterica or EHEC at 22 °C for 2 h with shaking at 40 rpm. Contaminated sprouts were thoroughly rinsed and homogenized in 0.1% peptone water, and bacteria attached to sprouts were enumerated. Biofilm mass accumulated on polystyrene surface increased with incubation time ( P < 0.05). Among the microbiological media used, LB no salt (NaCl) broth better supported biofilm development ( P < 0.05). Two EHEC strains formed more biofilms than the Salmonella and other two EHEC strains ( P < 0.05). However, more Salmonella cells (5.66 log CFU/g) attached to sprouts than EHEC cells (3.46 log CFU/g). Both Salmonella and EHEC attached in higher numbers to mung bean, than alfalfa, sprouts ( P < 0.05).