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< prev - next > Food processing KnO 100642_Smoked Foods (Printable PDF)
Smoked foods
Practical Action
The amount of smoke that is absorbed by a food depends on the density of the smoke, its
humidity and temperature: the higher the smoke density, the more is absorbed. If the smoke is
moist, it increases the amount of flavour compounds that are absorbed. Colour and flavour
development also depend on the moisture content of the food and there needs to be a balance
between smoke temperature and the surface moisture of foods: low surface moisture is needed
for colour formation, but if the surface is too dry, there is less penetration of the smoke
flavours into the food. Balancing these different factors makes smoking foods an art as much
as a science.
Traditional hot-smoking
Hot-smoked foods are heated to a temperature that is high enough to destroy micro-organisms
and cook the food (Table 1). Hot-smoked products can be stored without refrigeration for
several weeks. Curing with salt or brine is optional for these foods. If they are dry-salted they
should be soaked in fresh water to remove most of the salt before consumption. Smoking
produces a strong smoky taste, a golden brown to black colour and a silky sheen on the food
surface. An example is traditional West African hot-smoked pork shoulders, feet, head or offal,
which have well-developed smoky flavours and are used in soups or stews.
There are minimum temperatures and times needed for hot-smoking to destroy the particular
types of food poisoning (or ‘pathogenic’) bacteria that are likely to be found on the food: for
example, fish requires a process that gives an internal temperature of 60oC for at least 30 min
to destroy Listeria monocytogenes. However, most smoking times are much longer than this to
allow colour and flavour development (e.g. up to eight hours at 60-85oC) and all hot smoking
processes normally kill pathogenic bacteria. Preservation of hot-smoked foods is due to a
complex series of factors, including drying the surface of the food, the antimicrobial effects of
salt and heat, and the antioxidant and antimicrobial action of the chemicals in the smoke.
Type of food
Beef ribs
Chicken (legs, wings)
Chicken (quarters)
Chicken (whole)
Maize cob
Smoking time at a smoke
temperature of 107-121oC
3.3 h/kg
3.3 h/kg
Final product
temperature (oC)
Table 1. Smoking times for selected foods (Adapted from Phillips, undated)
Cold or warm smoking
Foods that are cold- or warm-smoked are not heated to a high enough temperature to destroy
micro-organisms and they need to be treated with salt (‘cured’) to prevent the growth of food
poisoning bacteria. In traditional methods, dry fine-grained salt with optional potassium
nitrate (saltpetre) is rubbed into all surfaces of the meat or fish before they are smoked. In