Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Hygienic Design as aTool in Improving
(Equipment) Surface HygieneGun Wirtanen
University of HelsinkiRuralia Institute,
Seinäjoki, Finland
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Factors Affecting the Hygienee.g. in Milking Equipment
Lay-out of processlines and equipment
Contamination e.g.- microbes- soil
Constructions
Cleaning &disinfecting practices
GMP &Employees
Lubricants
Equipmentsurfaces
Product
Cleanliness of process facilities,Water, steam and air quality
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Phases in theBiofilm Formation
Acc. to Busscer & van der Mei (2000) in"Initial microbial adhesion events:
mechanisms and implications".
In Proc. 59th SGM Symposium,p. 25-36, Cambridge University Press,
ISBN 0 521 79302 5.
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Biofilm Consists of:Ø MicrobesØ Extracellular polymers (EPS; polysaccarides,
glycoproteins etc. from microbes)Ø Water (85 - 98%)Ø Captured particles and other dissolved materials
from the process stream
b) the same biofilm after swabbinga) 6 d biofilm of Lactobacillus brevis
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Microscopying of 5 d Pseudomonas fragi biofilm stained with acridineorange on various stainless steel surfaces (AISI 304): (a) glass blasted,
b) lapped and c) mechanically polished
(acc. to Wirtanen, Saarela, Mattila-Sandholm. 2000. Biofilms – Impact on hygiene in food industries.In: Bryers (Ed.) Biofilms II: Process analysis and applications. Wiley-Liss Inc. Pp. 327-372.)
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Design & Construction -process lines and surfaces must be:
q Accessible
q Cleanable§ Smooth surfaces
§ No metal-to-metal contact
§ No steps/misalignment
§ Crevice free
§ Use rounded corners
§ Inclined
q Drainable
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Biofilm Effects in Food Processing
< cleaning and disinfection processes are affectedand the choice of chemicals, flow, time andtemperature must be altered
< increased need of maintenance in process linesand equipment e.g. prolonged down-time orlaborious demounting of equipment e.g. in heatexchangers, in water supply systems, in granularactivated carbon columns, in reverse osmosismembranes, in ion exchange systems, in waterstorage tanks and in microporous membrane filtersdue to cleaning and hygiene, energy losses
& blockages.
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Biofilm Effects in Food Processing
<energy losses in processing e.g. prolongedpasteurization
<deterioration on specific chemical reactionse.g. contamination of immobilized cell systems
<deterioration of products e.g. the product canbe of lowered quality already after production
< limited shelf-life of the products<occurrence of pathogenic microbes which
increase the risks of foodborne poisoning
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
What to Remove?Physically
Ø remove visible organic gross soile.g. fat, protein, sugar & carbohydrates
Ø remove visible inorganic residuese.g. mineral salts (milk stone)
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
What to Remove?Chemically
Ø remove crust e.g. milkstoneØ remove allergensØ allergens can be determined by using
specific protein assessment kitsØ remove cleaning agents through rinsingØ remove disinfectants through evaporation
or final rinsing (with potable)
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
What to Remove?Microbiologically
Ø reduce number of spoilage microbesto an acceptable levelØ can be determined usingØ culturing on agar plates
(nutrient or specific)Ø rapid tests (adenosine tri-phosphate
(ATP), protein residues etc.)Ø visual or organoleptic inspection
Ø free surfaces from pathogens
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
When to Clean Wet Surfaces?After production – daily cleaning
but also
cleaning during production –a) always when visible soil is seen in theprocess orb) when microbial growth is estimated toreduce quality of products produced
and periodic cleanings –c) of both process facilities and equipment
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
How to Clean?Ensure high quality and safe productsof high quality raw materials by:1. removing soil from2. removing / killing microorganisms from3. avoiding recontamination of
surfaces
by combining proper design andeffective cleaning & disinfectionthrough the whole processing.
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
èManual dry cleaning e.g. brushing orvacuum cleaning
èRemoval of gross soil from processfacilities through rinsing
èRemoval of visible soil from processfacilities through cleaning and rinsing
èCleaning of equipmentèRinsing of equipment
Phases in Open & Wet Cleaninge.g. Milk Tank Area
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
è Disinfection of equipment surfaces to kill livingresidual microbes
è Fogging i.e. disinfection of process facilitiesè Drying of equipment and processing facilities
using efficient air conditioningè Keep cleaned and disinfected process equipment
as dry and cool as possible to reduce regrowth.è Equipment parts should be stored on shelfs
NOT on the floor.
Phases in Open & Wet Cleaninge.g. Milk Tank Area
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Cleaning & Design as Tools inProcess & Equipment Hygiene
Ø An optimal solution is to have equipment exactlydesigned according to hygienic design principles:
Ø which is usually NOT feasible in practice - therewill always be compromises
Ø therefore, devices that as much as possible followthe hygienic design principles should be used
Ø It is also important to know the risks e.g.:q to deside when there is need for extra cleaningq use hard to clean places as control points when
checking cleaning efficacy
Ruralia Institute / Gun Wirtanen / Improved Surface Hygiene www.helsinki.fi/ruralia
Constructors &Equipment
Manufacturers
Food Producers –both Primary
Production andFood Processing
Cleaning &Maintenance
Services
Cleaning Agent& DisinfectantManufacturers
HygienicProcess
Solutions
Parties Involved in ImprovedFood Processing Hygiene
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