biofilms in food enviromment

7/28/2019 Biofilms in Food Enviromment

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BIOFILMS

IN THE

FOOD ENVIRONMBLESSING OR CU

By

Paul T. Asare

Food Material Science L

Dept. of Food Science and Tec

Chonbuk national Univer


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Presentation outline

Biofilms what are they? History of biofilms

Formation of biofilms

Detection of biofilms

Beneficial application of biofilms Harmful effects of biofilms

Ways of eliminating biofilms

Concluding remarks


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Biofilms what are they?

A matrix-enclosed bacterial populations adhered to a surfaceother.

Microbial derived sessile community which is characterized that are irreversibly attached to the substratum, interface or e

Keywords

microbial aggregate, flocculates and population adherent to mpores


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Biofilms what are they? Cont

Characteristic features of biofilmsa. Can be formed by all microorganisms be it spoilage and pa

microorganism

b. Can be found on both biotic and abiotic surfaces

c. Embedded within a self-produced matrix of extracellular p

substance (EPS)

d. Single species or multispecies

e. They are self regulating

f. Ability to attach and detach


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History of biofilms

First discovery on teeth by Anton Leeuwenhoek.

Zobel, 1943 reported biofilms in submerged surfaces.

Areas covered are

a. Dentistry

b. Medicine

c. Food science

Van Leeuwenhoek


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History of biofilms, cont

Research on biofilms in food science commerce in 1987 by Holaothers.

Biofilm forming bacteria of food safety importance

Pseudomonas

Listeria

Staphylococcus

Enterobacter

Flavobacterium

Alcaligens

Bacillus


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Aim: Protection from hostile environment and a trap of nutrienSteps in biofilm

a. Attachment

b. Micro-colonies formation and Exopolysaccharide producti

c. Maturation and detachment

Attachment

a. Reversible

b. Irreversible


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Formation of biofilms cont

Attachment influenced byBacteria surface structures

Flagella, fimbriae, curli, pili

Material property

Surface roughness

Environmental factors

Temperature, Osmolarity, pH, Iron and Oxygen


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Attachment

Reversible attachment

a. Long distance forces such as vahydrophobic interactions

b. Easily removed at this stage

Irreversible attachment

a. Short distance forces such as dihydrogen, ionic and covalent bohydrophobic interaction.

b. Difficult to remove


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Properties of the attachmentsurface

Surface conditioning

Surface roughness

Presence of soil

Cracks and curvatures inprocessing lines

Bacteria surface Flagella

Fimbriae

Curli

Pili


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Micro-colonies formation and exopolproduction

Mechanisms

Redistribution of attached cells by surfa

Binary division of attached cells

The recruitment of cells from bulk fluiddeveloping biofilms


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Maturationdetachment

Detachment

Caused by dof nutrient in

biofilm


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Biofilm formation cont

Video representation of biofilm formationNote: sensitive viewer discretion is advised


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Detection of biofilms

Transmission electron microscope Scanning electron microscope

Confocal laser scanning microscopy


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Beneficial application of biofilms cont

Biofilm reactors (Fukuda, 1995) Higher biomass density

Reduce risk of wash out in continues culture

Re-inoculation not needed

Decreased media viscosity (oxygen and nutrient utilization)

Easy recovery of product from biofilm reactors


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Beneficial application of biofilms

Biofilm reactora.fermentation and wastewater

treatment

Fermentation

a. Ethanol

b. butanol,c. lactic acid,

d. acetic acid/vinegar,

e. succinic acid, and fumaric acid

wastewater treatment the fixed-medium system

the biofilm media are stareactors and the biologictake place in the biofilm on the static media, and

the moving-medium syswhere the biofilm mediacontinually moving by mmechanical, hydraulic, o


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Beneficial application ofbiofilms cont

Particle-based biofilm reactor technology


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Beneficial application of biofilms cont

Energy generation: Bioenergy


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Harmful effects of biofilms

Continuous supply of microorganism Resistance of antimicrobial agents

Corrosion of metals

Reduction of heat transfer

Leading to the reduction in shelf life and disease transmission


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Biofilms removal and control

Cleaning Sanitizing

Equipment design

Monitoring

CleaningChemical and physical m

Steps

a. Washing

b. Rinsing

c. Sanitizing

d. Air drying


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Biofilm removal and control cont

Cleaning

Types of cleaner Soap/detergent

Acid cleaners

Heavy Duty Detergent

Abrasive cleaners

Degreasers

Success depends on

Formulation

Time

Frequency

Mode of application


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Sanitizing

Hot Water

Must maintain appropriate watertemperature

Chemical

Several different types

Chlorine Iodine

Quaternary ammonium compounds

AcidDetergent Sanitizer

Others

Success depends

A clean surface

Clean sanitizing solution

Proper strength of sanitizsolution

Proper water temperature

Sufficient contact time foeffectiveness


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Equipment design


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Concluding remarks

Biofilms can be beneficial in food processing as well as food conwhen considering it from the food processing and food safety per

Direct evidence that pathogen-containing biofilms play a role in tof foodborne illness is lacking, as identification and characterizat

biofilms has not been included in food borne illness investigation

There should be biofilm-supporting of food contact materials in a

thermal mechanical and chemical resistant

Identify biofilm prone areas and monitor their existence

Also the efficacy of cleaning agents and disinfectants should be atheir ability to decrease biofilm formation


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References

Biofilms in the food environment

Edited by Hans P. Blascheck, Hua H. Wang and Meredith E. ABlakwell publishing, 2012

R. van Houdt and C.W. Michiels, 2010. Biofilm formation an

food industry, a focus on the bacterial outer surface.JournalApplied Microbiology 1364-5072


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biofilms in food enviromment

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