Method for salting meat

Meat, especially pork, is cured by injection of saturated brine having microfine salt suspended therein. The method is especially advantageous when the meat is subsequently to be cured in a sealed plastic bag, and makes it possible to achieve salt contents not readily obtainable by other means.

This invention relates to the salting (curing) of meat, especially pork to 
produce bacon. As used herein, the term "bacon" is used generically to 
cover all pork-derived products which are sold after salting, e.g. gammon, 
collar, hock, and slipper, as well as the various forms of bacon itself. 
Meat is customarily preserved by treatment with salt. For this purpose the 
salt must penetrate the interior of the meat. To speed up this process, it 
is customary to inject brine, i.e. salt solution, into the meat through 
fine nozzles. The meat so injected may then be immersed in brine to 
complete the process. Current food regulations require that meat which 
contains more than 10% of added water must be labelled to show the amount 
of water added. It is therefore normal practice to sell meat containing 
not more than 10% of added water. The shelf life of salted meat depends 
upon the salt content. For a shelf life of about four weeks, which is 
appropriate for retailers who have a rapid turnover of stock, a salt 
content of about 2.5 to about 2.75% is adequate, but for a shelf life 
longer than this, e.g. six weeks, the salt content must be increased up to 
2.75 to 3.5% by weight. Such high salt contents cannot be achieved by 
injection of brine into meat, and it is necessary to follow such injection 
with an immersion in a brine bath if this level of salt is required. 
There has been considerable interest in recent years in curing meat inside 
sealed plastic bags. To operate this method, the meat is first injected 
with brine in the manner already described, and the injected meat is then 
placed in a plastic bag which is sealed and usually heat shrunk. After the 
salt has had time to permeate evenly through the meat, the cured meat may 
be removed from the bag and sliced and repackaged in the usual way. This 
method of curing meat has the advantage of greater cleanliness and 
avoiding the use of brine baths. However, it has not heretofore been 
possible to achieve salt contents over about 2.75% using this method of 
curing meat in a bag. The present invention provides a method of 
overcoming this problem. 
According to the present invention meat, especially pork, is cured by 
injection of saturated brine which has suspended therein salt particles 
capable of passing through a sieve having apertures of 100 micrometers, 
and preferably capable of passing through a sieve having apertures of 50 
micrometers. Such so-called "microfine salt" is commercially available for 
incorporation into butter where the fine particle size is required to 
permit homogeneous mixing and prevent any sensation of grittiness in the 
butter. Salt of ordinary particle size cannot be used in the present 
invention since it clogs the injection nozzles and cannot be 
satisfactorily injected into the meat. 
The suspension of microfine salt in brine may be made up at the time of 
use. The saturated brine itself may be made by dissolving ordinary coarse 
salt in water with the addition of the usual preservatives such as 
nitrates, nitrites and/or ascorbic acid in the usual amounts. The 
microfine salt is then added at a rate dependent upon the desired final 
salt content of the meat, usually at a rate of 20 to 80 parts by weight 
preferably 35 to 70 parts by weight, of microfine salt per 1000 parts by 
weight of saturated brine. As already indicated, the normal levels of 
preservatives may also be added to the injection mixture. Since there is a 
danger of recrystallization of the microfine salt if it remains suspended 
in the brine for any length of time, it is desirable to make up the 
suspension for injection only shortly before it is required for use. 
The present invention is especially advantageous for use with methods for 
curing meat, e.g. pork, in sealed plastic bags since it provides a 
solution to the above-mentioned problem, namely that salt levels above 
about 2.75% cannot be achieved using this method simply by injecting 
saturated brine into the meat. The invention thus makes it possible to 
produce bacon and other salted meats having a shelf life of six weeks 
using the method of curing meat in a sealed plastic bag. 
The following Examples describe in more detail the salting of meat using 
the method of the present invention.

EXAMPLE 1 
Joints of pork weighing 3 to 12 kg each and containing no bone were 
injected using a multi-needle injector (Formaco) with a brine mixture 
having the following composition: 
water: 740 parts by weight 
pure vacuum dried (PVD) salt: 260 parts by weight 
microfine salt: 64 parts by weight 
nitrate and nitrite: usual levels 
The PVD salt was dissolved in the water before the addition of the 
microfine salt. This suspension of microfine salt in brine at a 
temperature of +1.degree. C. to +2.degree. C. was injected into the meat 
held at a temperature of 4.degree. C. to 5.degree. C. The amount injected 
was such as to add to the meat 9.8% of water and 3.2% of salt. After 
injection the joints of meat were packaged in standard heat shrinkable 
plastic laminate bags (as sold under the registered trade mark Cryovac 
BBl). 
The joints subjected to this process were 10 middles, 10 backs, 10 streaks, 
10 legs and 10 fores. Analysis of the joints of meat after 7 days showed 
that the middles contained 3.1% to 3.2% salt, the backs 3.0% to 3.1% salt, 
the streaks 2.2% to 2.3% salt, the legs 2.3% to 2.7% salt, and the fores 
3.2% to 3.6% salt. The low figures obtained with the streaks can be 
accounted for by the presence of less lean meat in cuts of this kind. It 
is the lean meat that takes up the salt. The low FIGURE with the legs was 
attributable to variations in brine injection. As shown in Example 2, with 
careful control of brine injection the required salt level can be achieved 
without difficulty. 
EXAMPLE 2 
Pork sides divided into a variety of different cuts were injected with a 
brine comprising: 
water: 531 parts by weight 
PVD salt: 184 parts by weight 
microfine salt: 40 parts by weight 
nitrite: normal amount 
The brine temperature was +5.degree. C. and the meat temperature was 
3.degree. C. to 4.degree. C. A multi-needle Formaco injector was used, the 
objective being to add 10% of water and about 3.5% of salt to the meat. 
After injection, the major cuts were subdivided and enclosed in sealed 
plastic bags to complete the curing process. It was found that the middles 
took up 4.6% of salt, the backs 3.3% of salt, the streaks 2.3% of salt, 
the legs 3.8% of salt, the range of salt contents for the various cuts 
being from 2.3% to 4.6%. Again the low percentage of salt achieved with 
the streaks was attributable to the high proportion of fat in this cut. 
The present invention provides a significant improvement in the curing of 
meat, especially pork, in sealed plastic bags. Heretofore the inherent 
advantages of this method in terms of greater flexibility and better 
protection for the meat during the curing process have been to some extent 
reduced by the impracticability of achieving salt contents higher than 
about 2.75%. This obstacle has now been removed, and the method provides 
the meat processor with a way of curing meat which permits great 
flexibility especially in deciding whether given cuts of meat shall be 
sold as such or cured.