New paradigms for the design, manufacturing and operation of food processing and packaging equipment 8th Presentation of Final Workshop VERIFICATION OF HYGIENE AND SANITARY REQUIREMENTS AND OF PROCESSES QUALITY Laboratory tests and techniques Project web site: http://www.npfp.it/en

1. The evaluation of the hygienic design of food-
contact materials developed in NPFP project:
laboratory tests and techniques
Prof. Davide Barbanti
Centro SITEIA.PARMA - Università di Parma

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Why it is important to ensure
cleanability of innovative food contact
surfaces ?
- Safety and quality of foods
- Efficiency of Cleaning and Disinfection (C&D)
- reduce down-time and C&D costs
- Sustainability
- Reduce water usage
- Reduce chemical usage
- Reduce Energy usage
- Reduce waste-water treatment
- Reduce Food waste

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To facilitate the design, testing and maintenance of hygienic food-processing
equipment, it is important to be able to assess the relative cleanability of various
components of the equipment using standardized test procedures.
The test is designed to indicate areas of poor hygienic design of equipment in which product or
micro-organisms are protected from the cleaning process. It can also be used to compare the in-
place cleanability of different equipment designs.
The method is based on comparing (in the laboratory) the cleanability of a test item with that of a
straight piece of pipe.
The degree of cleanliness is based on the removal of a “soured milk soil” containing bacterial spores
and is assessed by evaluating the number of spores remaining after cleaning with a mild detergent.
The method is intended as a screening test for hygienic equipment design and is not indicative of
the performance of industrial cleaning processes (which depend on the type of soil).
EXAMPLE OF TEST METHOD FOR
ASSESSING THE IN-PLACE CLEANABILITY

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Comparative
Soil-ability and
Clean-ability test
development
Sample design
(If relevant)
Measurement of
soil-ability
Measurement of
clean-ability

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Spores visualization on the reference
material
Evaluation of 2 surfaces with same roughness (Ra)
and different topography
Example of high cleanable surface – A before cleaning, B- after cleaning
A B

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Cleanability test for Open Plant Cleaning
(OPC)
1) The sample is soiled with a
soured milk and then dried
with filtered dry air
2) The test rig reliably
simulates common Open
Plant Cleaning OPC
3) The surface is checked for
organic substance residues,
by bioluminescence
measurement

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50mm
100mm
50mm
100mm
Sample 1: Hydrophobic Laser-treated
surfaces
Reference 1 and 2: AISI 316L (Ra < 0.8 µm)
Laser treatment 1
Laser treatment 2
Sample description

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Sample soiling: the
sample was soiled with
soured milk and
drained.
Sample drying: the
sample was dried with 1
m/s dry air flow.
Cleanability assessment method description

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Soil-ability test: samples
were soiled and drained
in vertical position and
dried with dry filtered air
The milk layer flakes
due to high idrofobicity
of laser treated surface
Soil-ability

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At various concentration of organic substance in the soil
Black surface
Grey surface

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Cleaning phase of sample:
this phase simulates an
Open Plant Cleaning (OPC).
The cleaning operation was
performed with a
pressurized water jet.
Sample was placed on a
rotating base.
After cleaning procedure, milk residues were detected on the surfaces by means
of a bioluminometer. The residues were expressed in RLU (Relative Light Units)

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Results
Laser treatment 1 (grey surface)
data were not shown because after
cleaning there were visible milk
residues on it.
black surface

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Sample 2: Overlapped coupling with corner
A
B
C
Surface roughness measurement:
A) Ra= 1,41 µm
B) Ra= 0,3 µm
RLU post-cleaning
Sample description and results

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New sample:
overlapped coupling
without acute angles
and corners.
Reference
surface.
Surface whose
cleanability has to be
evaluated: flat
overlapped coupling
made by gluing
Overlapped coupling without corner
Sample description

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Post cleaning RLU at different milk dilution as soiling agent
Cleanability of sample Results
0
1000
2000
3000
4000
5000
6000
Prova 1 Prova 2 Prova 3
1:5
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
Prova 1 Prova 2 Prova 3
1:1
Incollaggio RiferimentoGlued
surface
Reference
surface

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Sample 3: additive manufacturing curved pipe
A. Townsenda, N. Seninb, L. Blunta, R.K. Leachb, J.S. Taylord
(2016), Surface texture metrology for metal additive
manufacturing: a review. Precision engineering, 46(2016), 34-
47.
The third sample was
impossible to evaluate
due to its surface high
roughness and porosity.
The experimental
sample has
incompatible
characteristics in food
application, and the
fabrication process
needs developments in
order to increase the
food compatibility of the
pipe.

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Conclusions
Sensitive methods are available to check cleanability of innovative
surfaces.
The technology itself and the manufacturing quality play a major
role on cleanability, since they affect surface quality
- Laser treated surfaces: some treated surfaces show
significant lower soil-ability, but also less clean-ability
- Bonded surfaces: manufacturing methods are not sufficiently
reliable in terms of surface quality.
- Clean-ability is mainly affected by the manufacturing quality
rather than by the bonding technology itself

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Further development
Innovative surfaces offer good opportunity for more efficient and
sustainable processes in the food industry.
Some further development is necessary to adopt innovative
surfaces at an industrial scale in the food sectors:
- Laser treated surfaces: develop new profiles with reduced
surface roughness or different topography in order to avoid
poor cleanability
- Bonded surfaces: improve manufacturing to allow smooth
surfaces without steps, crevices and glue residues
- Additive manufacturing: improve manufacturing process to
reduce porosity and surface roughness

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Thanks for your attention!
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