Dairy processing – an overview
Practical Action
All internal walls should be plastered or rendered with concrete that has no cracks that could
harbour dirt or insects. The lower parts of walls should either be tiled to at least 1.5 metres
above the floor, or painted with waterproof white gloss paint. Higher parts of walls can be
painted with good quality emulsion paint if tiling is too expensive. Windows should be screened
with mosquito mesh. Thin metal chains, or strips of plastic can be hung from door lintels to
deter flying insects, or alternatively, mesh door screens can be fitted. The floor should ideally be
tiled with floor tiles. However, these are expensive and may be slippery when wet. Good quality
concrete, smooth finished and without cracks can be used instead. Vinyl-based floor paints can
be used to protect floors, but they are expensive. Red wax household floor polishes should not be
used because they wear away easily and could contaminate products.
Proper drainage prevents pools of stagnant water forming, which would allow insects and micro-
organisms to breed. The floor should have a 2-3% slope to drain water to a drainage channel,
which is covered with a metal grating that can be removed to clean the drain. A wire mesh cover
should be fitted over the drain exit to prevent rodents and crawling insects getting into the
building through the drain. This should also be easily removed for cleaning.
Milk in
Milk cold store Product cold
store
Office/Retail sales
Drain
Yoghurt
incubator
Spares and tools
QA testing
Cream Butter Cheese Cheese Boiling
separator churn vat
press pan
Cleaning
materials
Packaging
Figure 1: Layout of a small dairy
From: Opportunities in dairy processing
Packaging store
Washroom & toilet
An adequate supply of clean water of drinking quality should be available from taps in the
processing room (2-5 litres of water are required to process one litre of milk at a small scale of
operation). Hosepipes with pistol grip adjustable sprays should ideally be used for washing down
floors and equipment. If necessary, water should be treated to remove bacteria. The cheapest
and easiest way is to use bleach (also known as ‘chlorine solution’ or ‘hypochlorite’). Bleach is
cheap and effective against a wide range of micro-organisms. Water for cleaning should contain
about 200 ppm (mg/litre) of chlorine, made by mixing 1 litre of bleach into 250 litres of water.
Commercial treatment units that use ultra-violet light to destroy micro-organisms in water are
suitable for larger-scale processors that use a lot of water.
Equipment
All dairy equipment should be designed and constructed so that it can be easily dismantled for
cleaning (e.g. there should be no blank ends to pipework that would harbour stagnant milk).
Mixing bowls, boiling pans etc. should have a smooth internal surface without corners, and all
welds should be ground to a smooth finish. Ideally, all dairy equipment should be made from
stainless steel, but alternatives include polished aluminium, or food grade plastic for containers
and equipment that are not heated. Mild steel cannot be used because it will rust and
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