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< prev - next > Food processing KnO 100644_Baking (Printable PDF)
Practical Action
under strict hygienic conditions and cooled and packaged as soon as possible. It is essential that
they are adequately cooled before packaging. If warm products are packaged, moisture can condense
on the inside of the pack, which would wet the food and lead to mould growth. The dry crust of bread
and some other bakery products acts as a barrier to contamination by micro-organisms during
storage, but migration of moisture from the interior of the product, or from high-moisture fillings in
cakes and pastries, can allow spoilage by moulds. These products should be chilled or frozen to
reduce this. Pies and samosas should be either kept in a refrigerator or stored in a hot display
cabinet (above 63°C). Obtaining high quality ingredients, handling food safely, good temperature
control and thorough cleaning are essential if these products are to be produced safely. Some baked
products, such as cakes, may also contain preservatives including calcium propionate that is
effective against moulds, or potassium sorbate that is effective against yeasts, moulds and some
bacteria. However, these are not widely used at small scales of production.
Ingredient inspection
Most small bakers either buy flour directly from a local miller and other ingredients, such as special
fats, sugar, salt, essences and yeast are purchased from wholesalers, retailers or from import agents.
Management of bakery storerooms should comply with the following:
Store sacks of flour on pallets away from walls to prevent dampness and allow easy cleaning
around and underneath the sacks.
Use stock rotation - first-in-first-out (FIFO)
Ensure that the storeroom is dark and cool without temperature fluctuations
Ensure that all rooms are sealed against insects, birds and rodents and that doors are not left
open when not in use.
Clean the processing room each day and the storeroom each week.
Small-scale bakers often have little control over the quality of ingredients that are supplied and
therefore need to conduct checks to ensure they are of a suitable quality. The following tests are
suitable for because they are relatively simple to use; they are sufficiently accurate for quality control
purposes; they do not require sophisticated or expensive equipment; they do not require a high level
of skill and they are relatively inexpensive.
Before use, flour should be checked for visible signs of flour mites, mould and for a mouldy or rancid
smell. To test for the presence of flour mites, place a sample of flour onto a flat surface and use a
ruler to spread it out and flatten it. Examine the flour for evidence of pimpling (disturbance of the
surface) after about two minutes, which indicates the presence of live flour mites breaking the
surface for air. The ‘filth’ test detects dead flour mites, insect parts, rodent hairs or faeces in flour:
Mix a sample of flour with petrol in a glass jar and stir thoroughly. When the suspension of particles
settles, the contaminants may be seen floating on the surface of the petrol. If required they may be
filtered out and identified. The ‘sieving’ test can be used to detect contamination with stalks, stones,
string, leaves etc. as well as measuring the degree of fineness of the flour. However, the cost of
specialist laboratory sieves is relatively high and the investment can only be justified if there are
recurring problems with suppliers. Sieve flour through a stack of analytical metal sieves, with the
largest mesh size (1.6 mm) at the top of the stack and the smallest (0.038 mm) above the base.
Weigh the material that is collected on each sieve and express it as a percentage of the total weight.
Contaminants are retained on the larger sieves and can be examined if necessary. For bread-making,
it is important that a baker buys ‘strong’ flour with a medium to high gluten content. For other
products, ‘weak’ flour (lower in gluten) is normally used. Hard wheat flour is often more expensive
and difficult to obtain, and it is not unknown for a supplier to substitute cheaper soft wheat flour, or
to make an error when labelling the sacks. The gluten content can be checked by washing out the
starch from the dough and examining the gluten that remains. Weigh the gluten and record this as a
percentage of the flour weight (for a strong flour it should be 12-13% and for a weak flour 9-10%).
Solid shortenings (fats) and oils can rapidly develop rancidity if exposed to heat or sunlight, and
should be checked routinely by smell and taste. Any rancid fat should be discarded as it will impart
an unpleasant flavour to the products. Shortenings and oils should be stored in a cool place away
from sunlight, preferably in a refrigerator, and used as quickly as possible, with strict stock rotation
to prevent losses.