FOOD PRESERVATION:

SMOKING

Slow cooking of food indirectly over a fireNatural method: exposing food to wood smoke which

causes the deposition of pyroligneous acid on the food’s surface which acts as preservative and flavoring agent

Pyroligneous acid/wood vinegar: a red-brown liquid formed in distillation of wood which contains acetic acid, methanol, acetone, wood oils and tars

It is produced through the natural act of carbonization during charcoal/biochar production - this occurs when wood/biomass is heated in an oxygen starved environment

Artificial method: incorporating artificial smoke flavor in the pumping pickle for ham and bacon at the rate of 1 tsp/L

SMOKING

EXAMPLES OF SMOKED FOOD

INTERNAL TEMPERATURES FOR SMOKE COOKING OF FOODS 

1. Heat - kills bacteria & other microorganisms (depending on smoking time & temperature)

2. Chemical - antimicrobial effect of chemical compounds from smoke, but they are insufficient in themselves to preserve food

3. Surface dehydration - outer surface of food dries,  reducing moisture available for bacteria to grow

MECHANISM

To preserve and increase shelf life of foodTo impart desired and distinctive sensory

characteristics (flavor and aroma)

PURPOSE

1. Product preparation2. Salting or brining3. Equilibration and drying4. Smoking and cooking (hot or cold smoke)5. Product packaging and storage

SMOKING PROCESS (FISH)

Rinsing and cleaning (fresh meat or fish)Thawing (frozen)Cutting into desired size, deboningMany fish contain tapeworms and nematodes that can

survive low-salt brining and low-temperature smoking methods and may cause serious health problems. These parasites can be destroyed by freezing the raw product at a temperature of 0°F for two weeks or longer, before salting and smoking.

PRODUCT PREPARATION

High levels of salt inhibit bacterial growth For modern lower salt methods, salt reduces bacteria but, it

contributes desirable texture and flavor characteristics can be accomplished using either a strong salt solution (brine)

or dry salt brining gives a more uniform salting and is easier to prepare

and use dry salting requires considerable experience for consistent

results Brines preparation: dissolve salt in fresh water. Use pure salts

like kosher, vacuum-dried, dairy, pickling or canning salt only, not rock, sea and iodized salt which contain impurities & additives that can cause bitterness and “off” flavors. Curing salts should also be avoided since they contain nitrites. It is difficult to get an even distribution of nitrite throughout the fish under home conditions (for small scale).

SALTING

Fish is usually dried before smoking. Drying accomplishes two things: (1) it allows the salt to penetrate and to become evenly distributed throughout the flesh of the fish (equilibration), and (2) the surface of the fish dries to form a “pellicle” or tough shiny coat. The pellicle seals in moisture and makes the appearance of the finished product much better.

Refrigerate the fish during equilibration

DRYING

Cold-Smoking most often used for salted

products done over a longer period of

time (ex. 12-24 hours) over a smoldering fire

Since foods are held in lower temperatures, rapid microbial growth could occur. Therefore, only those meat products that have been fermented, salted, or cured, should be cold-smoked. 

meat: flesh temperatures of up to 30°C

fish: below 30°C usually employed for non-fatty

fish (ex. grayling, halibut)

Hot-Smoking primarily used for fresh or

frozen foods done in the smokehouse or

more modern electric kilns over a short period of time, just until the meat/fish is cooked over a burning fire or electric elements of a kiln

meat: flesh temperatures up to 90°C

fish: greater than 80°C Usually employed for fatty

fis

SMOKING: 2 TYPES

Most smoked products have no preservation step since there is not enough salt, smoke or heat to preserve the product. The potential for bacterial spoilage and botulism exists.

After the fish has been smoked, it is allowed to cool to room temperature to prevent condensation formation.

Followed by fish being wrapped with plastic/aluminum foil, may be vacuum-wrapped, and refrigerated or frozen until consumed.

Lightly salted and smoked products can last for 10 to 14 days in the refrigerator.

PRODUCT STORAGE

http://extension.usu.edu/foodpreservation/htm/cure-smoke-foods

Industrial Chemical Processes: Food Industries by Cecilia V. Bayqueen, Ph.D.

http://www.uaf.edu/files/ces/publications-db/catalog/hec/FNH-00325.pdf

REFERENCES