Agriculture Reference
In-Depth Information
be automatically controlled and dosed by conductivity
probe, with the probe being cleaned regularly and the
concentration checked. Location of the probe is impor-
tant in obtaining representative readings. Machines
should be set up for individual tray type; in this respect,
nozzle positions, angles and spray patterns are crucial to
obtaining a consistent hygiene result. If tray type and
shape change significantly, the machine will need to be
reset in order to maintain the required efficacy.
provides an equivalent food safety result. Turning off the
steam or electrical elements in traditional knife disinfec-
tion baths can contribute significantly to the reduction
of a plant's carbon footprint while also gaining other
benefits for operators and product.
Machine washing
Industrial machine washing is typically done with an
automatic or semi-automatic continuous tray wash or
buggy wash machine with spray nozzles arrayed on
booms in separate chambers of the machine or in sepa-
rate cycles for detergent, rinse and sometimes disinfect-
ant. An alternative machine design uses submersion
tanks or flumes, through which the trays are slowly
pulled. A less effective design is the circular carousel,
which runs the risk of contamination of clean trays by
dirty ones as there is only one entry/exit point. Other
machines, especially for buggies and racks, may wash
each item individually in a batch process. All machine
types represent an expensive capital investment and are
critical to the hygiene of direct food contact surfaces.
Wash machines generally are large consumers of water,
especially if not properly maintained and controlled.
Filters should be cleaned regularly and blocked nozzles
cleared. Prevention of liquid carry-over from one cham-
ber to the next is also important. Tray wash machines can
also be a contamination risk to the rest of the factory as
they can produce large quantities of fine, contaminated
aerosols, which may drift with natural airflows into
critical areas. Chemicals used in these machines must
be low foam or even actively de-foaming and should
Cleaning-in-place (CIP)
CIP is used extensively for the interior cleaning of pipes,
vessels, tankers, heat exchangers, fillers, etc. commonly
found in breweries and dairies for the processing of
liquid products. This approach is used in meat and poul-
try plants where giblets or other materials such as bast-
ing oils may be automatically transferred through pipe
systems. The most recent adoption of CIP in food manu-
facturing is in the convenience foods department where
sauces or marinades may be made. CIP involves a pro-
grammed cycle, including timed pre-rinse, cleaning and
rinsing stages, and is nowadays usually automated or
semi-automated with a system of valves, pumps and
detergent tanks, often controlled by microprocessor
(Lorenzen, 2005) (Fig. 5.8).
The main points to consider include the following:
Flow velocity
- It should be sufficient all parts of the
system to cause turbulent flow. This is generally around
1.5-2 m/s. Where pipe diameters vary in the one system,
the largest pipe should have this flow rate. Failure to
comply with this flow rate means smooth 'laminar' flow
Multiple use of cleaning solutions and rinse water
Detergent
Pre-rinse water
Object to be cleaned
Fresh water
Disinfectant
CIP-supply
CIP-return
Figure 5.8
Diagrammatic representation of a standard CIP system (Reproduced with permission from Ecolab. © Ecolab).
