TY - GEN
T1 - Hygiene Survey in Food Plants
AU - Salo, Satu
PY - 2014
Y1 - 2014
N2 - Food safety is related to the absence or presence of
levels of foodborne hazards in food at the point of
consumption. The EC Regulation 852/2004 covers the
principal objective of the general hygiene rules to
ensure a high level of consumer protection with regard to
food safety. However, food safety is the joint
responsibility of many people and it is principally
ensured through the combined efforts of all the parties
in the food chain. Legislative demands set the basic
requirements for the manufacturing of safe food products
whereas food safety management systems and food safety
guidelines and standards based on given legislation help
the food industry to keep up with current food safety
requirements. Hygiene survey is a practical tool for
controlling hygiene in food plants. By using an efficient
sampling of the surfaces of the process line, it is
possible to reduce the amount of low-quality food leaving
the plant. Hygiene survey can include checking of the
amount of surface-attached soil including protein,
polysaccharides, other organic and inorganic residues,
biofilm, dead and/or living microbes in general, or
specific pathogens and other harmful microbes. Hygiene
survey also helps with tracing contamination sources and
in optimising cleaning systems. There are several sources
of microbial contamination: raw materials, process
equipment, environmental surfaces, air, personnel and the
final product. In some cases demands for better hygiene
have been made because of prolonged shelf-life of
products, centralized production and long-distance
transportation, less time spent on cleaning and demands
for environmentally safe cleaning agents (Salo, 2006).
Quantification of the actual number of microbes from
surfaces is difficult due to strong microbial adherence
of biofilms. In addition, detection of biofilms using
traditional swabbing method often gives incorrect results
due to strong microbial adherence. Most techniques
underestimate the number of microbes on a surface.
Hygiene surveys from surfaces are challenging; the
measuring should be quickly performed, directly from the
surface and without damaging the surface, and the
microbes need to be detached completely. However, it is
difficult to measure biofilm and biotransfer potential
because the conventional microbiological methods used to
assess equipment hygiene have not been developed for
detecting biofilm. Reliable results are only possible if
the biofilm is properly detached and the cultivation is
performed under reproducible conditions or if the
measurement can be performed without detaching the
microbes. Microscopy is very often used as a reference
method for swabbing and cultivation. It has been reported
that the cells counted by direct microscopy consistently
give results one log unit higher than the cultivation
methods. Moreover, observations of surfaces using
epifluorescence microscopy have clearly revealed that
even when vigorous swabbing is applied only a small part
of the actual biofilm including the cells in it is
detached (Wirtanen, 1995). On the other hand, use of
excessive agitation and strong chemicals for detachment
of surface-adherent cells may harm the cells, thus making
them unable to grow in the cultivation procedure.
Choosing sampling sites in food plants and especially in
equipment with complicated structures is challenging,
since most likely the microbial residues are in
curvatures, con-nections, propellers, or on uneven
surfaces which are not easy to reach with sampling tools.
Quantification of the swabbed areas in places like these
is challenging. Contact agar applications with ridged
frames are only suitable for sampling of smooth and
straight surfaces (Salo et al., 2008). Preventive
risk-based food safety management systems such as HACCP
require that hygiene monitoring should provide results
rapidly in order to be able to perform corrective
actions. ATP bioluminescence and protein detection kits
for instance can provide a real time estimation of
overall cleaning efficacy or protein residues,
respectively. The detection and enumeration of indicator
organisms is widely used to assess the efficacy of
sanitation procedures. Escherichia coli counts can be
used as an indirect measure of faecal contamination. The
use of Enterobacteriaceae as hygiene indicators instead
of coliforms or E. coli yields much more precise results.
Interpretation of the results from hygiene monitoring is
often carried out case by case since there are quite many
factors affecting an acceptable level of cleanliness. The
ac-ceptable level depends on the purpose of the surface.
The surfaces in contact with ready-to-eat food products
must be much cleaner than other surfaces in the process
plant in contact with products which will be pasteurised
or surfaces in no direct contact with foods. Special
attention should also be paid to the surfaces next to
food contact surfaces since there is a high risk of
spreading contamination to food products (Salo et al.,
2006). The cleanliness level of the processed product
depends also on the spoilage sensitivity and the wanted
self-life of the product. The available recommended
guidelines and standards for aerobic colony counts for
clean surfaces vary widely, being 0 - 80 CFU/cm2
(Griffith, 2005). The threshold limit for clean surface
must be based upon a perception of a specific risk and
the decided acceptable level. Alternatively, microbial
yield obtained from surface after correct imple-mentation
of a well-designed cleaning programme can be used as a
desired value (Griffith, 2005). Comprehensive studies
performed by Griffith (2005) have indicated that in many
cases levels of
AB - Food safety is related to the absence or presence of
levels of foodborne hazards in food at the point of
consumption. The EC Regulation 852/2004 covers the
principal objective of the general hygiene rules to
ensure a high level of consumer protection with regard to
food safety. However, food safety is the joint
responsibility of many people and it is principally
ensured through the combined efforts of all the parties
in the food chain. Legislative demands set the basic
requirements for the manufacturing of safe food products
whereas food safety management systems and food safety
guidelines and standards based on given legislation help
the food industry to keep up with current food safety
requirements. Hygiene survey is a practical tool for
controlling hygiene in food plants. By using an efficient
sampling of the surfaces of the process line, it is
possible to reduce the amount of low-quality food leaving
the plant. Hygiene survey can include checking of the
amount of surface-attached soil including protein,
polysaccharides, other organic and inorganic residues,
biofilm, dead and/or living microbes in general, or
specific pathogens and other harmful microbes. Hygiene
survey also helps with tracing contamination sources and
in optimising cleaning systems. There are several sources
of microbial contamination: raw materials, process
equipment, environmental surfaces, air, personnel and the
final product. In some cases demands for better hygiene
have been made because of prolonged shelf-life of
products, centralized production and long-distance
transportation, less time spent on cleaning and demands
for environmentally safe cleaning agents (Salo, 2006).
Quantification of the actual number of microbes from
surfaces is difficult due to strong microbial adherence
of biofilms. In addition, detection of biofilms using
traditional swabbing method often gives incorrect results
due to strong microbial adherence. Most techniques
underestimate the number of microbes on a surface.
Hygiene surveys from surfaces are challenging; the
measuring should be quickly performed, directly from the
surface and without damaging the surface, and the
microbes need to be detached completely. However, it is
difficult to measure biofilm and biotransfer potential
because the conventional microbiological methods used to
assess equipment hygiene have not been developed for
detecting biofilm. Reliable results are only possible if
the biofilm is properly detached and the cultivation is
performed under reproducible conditions or if the
measurement can be performed without detaching the
microbes. Microscopy is very often used as a reference
method for swabbing and cultivation. It has been reported
that the cells counted by direct microscopy consistently
give results one log unit higher than the cultivation
methods. Moreover, observations of surfaces using
epifluorescence microscopy have clearly revealed that
even when vigorous swabbing is applied only a small part
of the actual biofilm including the cells in it is
detached (Wirtanen, 1995). On the other hand, use of
excessive agitation and strong chemicals for detachment
of surface-adherent cells may harm the cells, thus making
them unable to grow in the cultivation procedure.
Choosing sampling sites in food plants and especially in
equipment with complicated structures is challenging,
since most likely the microbial residues are in
curvatures, con-nections, propellers, or on uneven
surfaces which are not easy to reach with sampling tools.
Quantification of the swabbed areas in places like these
is challenging. Contact agar applications with ridged
frames are only suitable for sampling of smooth and
straight surfaces (Salo et al., 2008). Preventive
risk-based food safety management systems such as HACCP
require that hygiene monitoring should provide results
rapidly in order to be able to perform corrective
actions. ATP bioluminescence and protein detection kits
for instance can provide a real time estimation of
overall cleaning efficacy or protein residues,
respectively. The detection and enumeration of indicator
organisms is widely used to assess the efficacy of
sanitation procedures. Escherichia coli counts can be
used as an indirect measure of faecal contamination. The
use of Enterobacteriaceae as hygiene indicators instead
of coliforms or E. coli yields much more precise results.
Interpretation of the results from hygiene monitoring is
often carried out case by case since there are quite many
factors affecting an acceptable level of cleanliness. The
ac-ceptable level depends on the purpose of the surface.
The surfaces in contact with ready-to-eat food products
must be much cleaner than other surfaces in the process
plant in contact with products which will be pasteurised
or surfaces in no direct contact with foods. Special
attention should also be paid to the surfaces next to
food contact surfaces since there is a high risk of
spreading contamination to food products (Salo et al.,
2006). The cleanliness level of the processed product
depends also on the spoilage sensitivity and the wanted
self-life of the product. The available recommended
guidelines and standards for aerobic colony counts for
clean surfaces vary widely, being 0 - 80 CFU/cm2
(Griffith, 2005). The threshold limit for clean surface
must be based upon a perception of a specific risk and
the decided acceptable level. Alternatively, microbial
yield obtained from surface after correct imple-mentation
of a well-designed cleaning programme can be used as a
desired value (Griffith, 2005). Comprehensive studies
performed by Griffith (2005) have indicated that in many
cases levels of
M3 - Conference article in proceedings
SN - 978-951-38-8142-9
T3 - VTT Technology
SP - 139
EP - 141
BT - 45th R3Nordic Symposium
A2 - Wirtanen, Gun
A2 - Salo, Satu
PB - VTT Technical Research Centre of Finland
CY - Espoo
T2 - 45th R3Nordic Symposium
Y2 - 19 May 2014 through 20 May 2014
ER -