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Microbial biofilms in seafood: A food-hygiene challenge
Mizan, Md. Furkanur Rahaman,Jahid, Iqbal Kabir,Ha, Sang-Do Elsevier 2015 FOOD MICROBIOLOGY Vol.49 No.-
<P><B>Abstract</B></P> <P>Seafood forms a part of a healthy diet. However, seafood can be contaminated with foodborne pathogens, resulting in disease outbreaks. Because people consume large amounts of seafood, such disease outbreaks are increasing worldwide. Seafood contamination is largely due to the naturally occurring phenomenon of biofilm formation. The common seafood bacterial pathogens that form biofilms are Vibrio spp., Aeromonas hydrophila, Salmonella spp., and Listeria monocytogenes. As these organisms pose a global health threat, recent research has focused on elucidating methods to eliminate these biofilm-forming bacteria from seafood, thereby improving food hygiene. Therefore, we highlight recent advances in our understanding of the underlying molecular mechanisms of biofilm formation, the factors that regulate biofilm development and the role of quorum sensing and biofilm formation in the virulence of foodborne pathogens. Currently, several novel methods have been successfully developed for controlling biofilms present in seafood. In this review, we also discuss the epidemiology of seafood-related diseases and the novel methods that could be used for future control of biofilm formation in seafood.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bacterial biofilms contaminate seafood. </LI> <LI> Most <I>Vibrio</I> spp. form biofilms on seafood. </LI> <LI> Numerous factors affect biofilm formation on seafood. </LI> <LI> Use of novel biofilm-reducing methods could minimize seafood-borne diseases. </LI> </UL> </P>
Mizan, Md. Furkanur Rahaman,Jahid, Iqbal Kabir,Kim, Minhui,Lee, Ki-Hoon,Kim, Tae Jo,Ha, Sang-Do Taylor Francis 2016 BIOFOULING -CHUR- Vol.32 No.4
<P>Vibrio parahaemolyticus is one of the leading foodborne pathogens causing seafood contamination. Here, 22 V. parahaemolyticus strains were analyzed for biofilm formation to determine whether there is a correlation between biofilm formation and quorum sensing (QS), swimming motility, or hydrophobicity. The results indicate that the biofilm formation ability of V. parahaemolyticus is positively correlated with cell surface hydrophobicity, autoinducer (AI-2) production, and protease activity. Field emission scanning electron microscopy (FESEM) showed that strong-biofilm-forming strains established thick 3-D structures, whereas poor-biofilm-forming strains produced thin inconsistent biofilms. In addition, the distribution of the genes encoding pandemic clone factors, type VI secretion systems (T6SS), biofilm functions, and the type I pilus in the V. parahaemolyticus seafood isolates were examined. Biofilm-associated genes were present in almost all the strains, irrespective of other phenotypes. These results indicate that biofilm formation on/in seafood may constitute a major factor in the dissemination of V. parahaemolyticus and the ensuing diseases.</P>
Mizan, Md Furkanur Rahaman,Ashrafudoulla, Md,Sadekuzzaman, Mohammad,Kang, Iksoon,Ha, Sang-Do Elsevier 2018 Food Control Vol.89 No.-
<P><B>Abstract</B></P> <P>The aim of this study was to evaluate the promotive and/or inhibitory effects of NaCl, glucose, their combinations on biofilm formation and quorum sensing (QS) autoinducer-2 (AI-2) production on black tiger shrimp surfaces, using three strains of <I>Vibrio parahaemolyticus</I>. Initially, six different NaCl concentrations (0.5, 1, 2, 3, 4, and 5%) were evaluated for a maximum biofilm formation (∼6.3 log CFU/cm<SUP>2</SUP>) at 30 °C. Inhibitory effects of glucose at six different levels (0.005, 0.01, 0.015, 0.02, 0.025, and 0.05%) were then investigated using the NaCl level previously found for a maximal biofilm formation. <I>V. parahaemolyticus</I> formed the best biofilm at 2% NaCl and the least biofilm at 5% NaCl, regardless of <I>vibrio</I> strain. In combination of 2% NaCl and glucose at different levels, the largest biofilm was observed at 0.015%, with the least biofilm seen at 0.05%, regardless of <I>vibrio</I> strain. Addition of salt and glucose more than the optimal level (2% salt and 0.015% glucose at 2% salt) inducted a stepwise inhibition of <I>vibrio</I> growth and biofilm formation in a continuous matter. In the visual evaluation, similar results were observed for <I>vibrio</I> growth, biofilm formation, live/dead cell detection, and quorum sensing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Combined effect of NaCl-Glucose were studied on <I>V. parahaemolyticus</I> biofilm and quorum sensing. </LI> <LI> AI-2 detection was performed by HPLC-FLD. </LI> <LI> FESEM and CLSM analysis were investigated for visual observation. </LI> </UL> </P>
Sadekuzzaman, Mohammad,Mizan, Md Furkanur Rahaman,Kim, Hyung-Suk,Yang, Sungdae,Ha, Sang-Do Elsevier 2018 FOOD SCIENCE AND TECHNOLOGY -ZURICH- Vol.89 No.-
<P>Owing to their preservative and antimicrobial effects, essential oils (EOs) are promising natural ingredients for the food industry. The main objective of this study was to investigate the activity of thyme and tea tree oils against selected foodborne pathogens in biofilm mode. The major compounds of these EOs were analyzed by gas chromatography-mass spectrometry (GC-MS) and their antimicrobial activity was determined by a standard broth dilution assay. Biofilms were formed by Escherichia coli 0157:117, Listeria monocytogenes, and Salmonella spp. on abiotic surfaces and were treated with EOs at the minimum inhibitory concentration (MIC) and 0.1% (v/v) for 2 h. Our results demonstrate that EO treatment reduced biofilm cells up to 3.5 log CFU/cm(2), 2.1 log CFU/cm(2), and 2.5 log CFU/peg on stainless steel (SS), rubber, and minimum biofilm eradication concentration (MBEC (TM)) surfaces, respectively. Structural changes of the biofilm after exposure to EOs was confirmed by field emission scanning electron microscopy and viability of biofilm cells was observed using a confocal laser scanning microscope. Overall, these results suggest that EOs could be used to reduce foodborne pathogens in biofilms.</P>
Jahid, Iqbal Kabir,Mizan, Md. Furkanur Rahaman,Ha, Angela J.,Ha, Sang-Do Elsevier 2015 FOOD MICROBIOLOGY Vol.49 No.-
<P><B>Abstract</B></P> <P>The aim of this study was to determine the effect of salinity and age of cultures on quorum sensing, exoprotease production, and biofilm formation by <I>Aeromonas hydrophila</I> on stainless steel (SS) and crab shell as substrates. Biofilm formation was assessed at various salinities, from fresh (0%) to saline water (3.0%). For young and old cultures, planktonic cells were grown at 30?°C for 24?h and 96?h, respectively. Biofilm formation was assessed on SS, glass, and crab shell; viable counts were determined in R2A agar for SS and glass, but <I>Aeromonas-</I>selective media was used for crab shell samples to eliminate bacterial contamination. Exoprotease activity was assessed using a Fluoro™ protease assay kit. Quantification of acyl-homoserine lactone (AHL) was performed using the bioreporter strain <I>Chromobacterium violaceum</I> CV026 and the concentration was confirmed using high-performance liquid chromatography (HPLC). The concentration of autoinducer-2 (AI-2) was determined with <I>Vibrio harveyi</I> BB170. The biofilm structure at various salinities (0–3 %) was assessed using field emission electron microscopy (FESEM). Young cultures of <I>A.?hydrophila</I> grown at 0–0.25% salinity showed gradual increasing of biofilm formation on SS, glass and crab shell; swarming and swimming motility; exoproteases production, AHL and AI-2 quorum sensing; while all these phenotypic characters reduced from 0.5 to 3.0% salinity. The FESEM images also showed that from 0 to 0.25% salinity stimulated formation of three-dimensional biofilm structures that also broke through the surface by utilizing the chitin surfaces of crab, while 3% salinity stimulated attachment only for young cultures. However, in marked contrast, salinity (0.1–3%) had no effect on the stimulation of biofilm formation or on phenotypic characters for old cultures. However, all concentrations reduced biofilm formation, motility, protease production and quorum sensing for old culture. Overall, 0–0.25% salinity enhanced biofilm formation and expression of quorum sensing regulatory genes in young cultures, whereas these responses were reduced when salinity was >0.25%. In old cultures, salinity at any concentrations (0.1–3%) induced stress in <I>A.?hydrophila</I>. The present study provides insight into the ecology of <I>A.?hydrophila</I> growing on fish and crustaceans such as shrimp and crabs in estuarine and seawater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Salinity controls biofilms formation by <I>Aeromonas hydrophila</I>. </LI> <LI> Planktonic age is important for controlling biofilms and quorum sensing. </LI> <LI> Salinity modulates quorum sensing, motility and exoprotease activity. </LI> <LI> Water salinity contributes to biofilms formation on crab shell by <I>A.?hydrophila</I>. </LI> </UL> </P>
Effectiveness of a phage cocktail as a biocontrol agent against <i>L. monocytogenes</i> biofilms
Sadekuzzaman, Mohammad,Yang, Sungdae,Mizan, Md. Furkanur Rahaman,Kim, Hyung-Suk,Ha, Sang-Do Elsevier 2017 FOOD CONTROL Vol.78 No.-
<P>Listeria monocytogenes can persist and form biofilms in a food environment which are difficult to eradicate because biofilms are inherently resistant to a variety of antimicrobial treatments. Therefore, alternative approaches such as bacteriophages have been suggested as a promising biocontrol agent against biofilms. The aim of this study was to evaluate the efficacy of a cocktail bacteriophage product (ListShield (TM)) against L. monocytogenes biofilms. These biofilms were established on lettuce, stainless steel, rubber, and a MBEC biofilm device and exposed to the ListShield (TM) phage preparation (1 x 10(8) PFU/mL) for 2 h. ListShield (TM) had sufficient potency to significantly reduce the biofilm (P < 0.05) in all cases. Biofilm reduction achieved after ListShield (TM) treatment on the stainless steel coupon was 1.9-2.4 log CFU/cm(2) and on the rubber surface approximately 1.0 log CFU/cm(2). Phage application on lettuce inactivated biofilm bacteria up to 0.7 log CFU/cm(2). These results suggest that bacteriophage preparation ListShield (TM) is an effective tool for the inactivation of L. monocytogenes biofilms in the food industry. (C) 2016 Elsevier Ltd. All rights reserved.</P>