Handbook of Meat Processing

354 Chapter 20

tion. The size of this area depends on the

different types of hams. Hams are classifi ed

by pH and weight, as the amount of salt is

proportional to each individual weight.

Pre - Salting

The main goal of this stage is the incorpora-

tion of nitrate on the surface of the ham.

Hams are weighed and then rubbed on their

external surface with the curing salt (a

mixture of sodium chloride and potassium

nitrate) to get a fi nal nitrate concentration of

150 mg kg^ −^1 inside the ham. Some nitrite may

also be added. In some cases, the curing salt

may be directly applied in the salting stage

(i.e., for French and country - style hams).

Nitrate is not a preservative but is slowly

reduced to nitrite by the enzyme nitrate

reductase, a bacterial enzyme present in the

natural fl ora (i.e., Micrococcaceae) of ham,

and thus serves as a slow source for the gen-

eration of nitrite inside the ham. Nitrite is

very effective as a protective agent against

botulism (Cassens 1995 ). The European

Union allows a maximum addition of

150 ppm potassium nitrate or 300 ppm for the

combination of potassium nitrate + sodium

nitrite, while the United States allows

156 ppm sodium nitrite (1/4 ounce per 100

pounds of meat).

Salting

This stage is carried out to assure the penetra-

tion of salt into the ham. Salt exerts important

functions in the ham, such as an initial reduc-

tion of a w and inhibition of the growth of

spoilage microorganisms; it facilitates the

partial solubilization of myofi brillar proteins

and gives a characteristic salty taste to hams.

The incorporation of salt depends on the

type of ham and the country of origin. For

instance, in the case of Parma hams, the

amount of salt to be added is proportional to

the weight of the ham. Salt is applied on the

external surface of the hams, spread evenly

Reception

This step is crucial because the entire process
depends on the quality of raw hams.
Refrigerated hams are stored for 1 – 2 days
at 2 – 4 ° C to reach a uniform temperature.
Frozen hams are allowed to thaw till they
also reach an internal temperature of about
2 – 4 ° C. Hams are registered on their surfaces
to facilitate traceability and are subjected to
pressing rollers for bleeding. Just before
salting, part of the skin is removed, in order
to allow salt penetration and water evapora-

Refrigerated ham

Frozen/thawed ham

Pre-salting

Salting

Drying

Extended ripening

Smoking

(optional)

Boning/slicing

Reception

Cure salt

Salt

Packaging

Final product to consumer

Figure 20.2. Process fl ow diagram for the process-
ing of dry - cured hams. Reproduced from F. Toldr á ,
Ham, in Food Product Manufacturing Handbook of
Food Product Manufacturing , vol. 2, edited by Y. H.
Hui, R. Chandan, S. Clark, N. Cross, J. Dobbs, W. J.
Hurst, L. M. L. Nollet, E. Shimoni, N. Sinha, E. B.
Smith, S. Surapat, A. Titchenal, F. Toldr á (New York:
John Wiley Interscience, 2007).