Mold Ripened Meat Products
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156. NOLI, RIPEIED FEAT PfiOCliCTS J. C. AYRES, E. A. LILLARD, L. LEISTNEE Molds or yeasts are frequently present in large amounts on the surface or in the interior of certain aged, cured meats such as "fermented" sausages and "country cured" hams and can be metabolically active during the long curing and ripening time of these meats. Provisionally, these fungi must be considered important for the determination of flavor, appearance, and wholesomeness of these meats. "Fermented" sausages or salami for which molds or yeasts are believed to be desirable, are traditionally produced in countries such as Hungary, Italy, Spain, Greece, Yugoslavia, Rumania and Czechoslovakia and, to a more limited extent, in certain localities of the U. S. The processing of these sausages in several European countries has been an industry for hundreds of years but is largely restricted in the U. S. to the San Francisco-Oakland Bay area, where scme ten manufacturers may be found. "Country cured" hams are dry-cured meats comonly produced in the southern U. S. and have a curing and ripening time of 1/2 to 2 years. Heavy mold growth on the surface of these hams, is often observed and is sometimes rega.rded as a sign of proper aging. Dry European type salami differs from all other sausages in that its surface is covered by a light grey mold mycelium. The micro- flora not only affects the appearance but also influences the orgaco- leptic qualities and weight losses of the product during aging. The control of mold growth on salami depends almost exclusively on experience acquired over many years of practice. Variable proportions of pork and beef may be used in the formulation of different types of fermented sausages. Usually, no water is added to the meat and the fat is incor- porated as discrete particles or pieces that range in size from 1/8 to 1/4 inch. Generally, these cubes are carefully mixed with the lean meat so that a marbling effect is given to the final product. Salt, spices, nitrite and nitrate are added during the mixing process. This suspension is kept at 37OF for several hours to allow the ingredients to mature. Then the sausage is stuffed into natural or artificial fibrous casing and hung over- night before cold smoking daily for 2 hours for 8-10 days (Hungarian salame). Otherwise, the product remains in a green room for 4-5 days where excess moisture drips from the meat tJhi1e a characteristic mold flora begins to grow on the casing (Italian salame) - the time varies for dif- ferent batches and for different types of sausage. After smoking or when visible growth is observed, the product is moved to an aging room for a further 30 to 60 day period of curing; the temperature of this room is con- trolled at 50-60°F and humidity at 75%. Too much humidity is undesirable since it results in excessive mold development and the presence of un- desired fluffy or darker growth on the casings. Curing the aging period, employees periodically check the salami for mold growth and determine when the sausages are mature and ready for marketing. 157. The production of "country cured" hams has been known for many years and the procedures adopted have become traditional in certain areas. These processors are entrepreneurs who have developed a product that has attained good local acceptance. Most of the plants do not slaughter hogs; instead they buy the hams according to certain specifications from local packers or from the big packers. A good, thick twenty pound ham which is not too lean, has a long shank, and a round cut butt end (typical country ham appearance) is preferred. Ordinarily, the processing season extends fromthe middle of November until the middle of January, and the early part of December is considered as the best time to start curing because then it is usually cool and dry, but not sufficiently cold to freeze the meat. The temperature should not be above 40°F or below 32OF. For curing on the flesh side and the hock end of each ham, three to four tablespoons of sugar cure is thoroughly rubbed in, After this curing mixture has "melted" into the ham, which usually takes about half an hour, sodium chloride is massaged on the flesh side and is deposited on the shank and the aitch bone opening: 4-1/2-5 pounds of sodium chloride are re- commended for a hundred pounds of pork. After application of the cure, each ham is wrapped in butcher paper and slipped into a cotton knit bag. After leaving overnight or for several days on tables or slats, the hams are hung, shank end down, in the ham house for six weeks or longer. Some processors hickory-smoke the hams every day or every other day with cool hickory smoke for one to three weeks. The hams stay in the smoke- house for as long as it takes to achieve the desired color. The smoking process is not regarded as essential or even important for the flavor of the hams but enhances the appearance of the cured product and is used to promote advertising. After smoking, the hams are hung in the aging room. The aging time varies from a minimum of six months and may extend to two years in duration. The length of the period that a ham is aged depends to a great extent on its size and fat content. After two years of aging, the hams are still considered of high quality and have intense flavor. When hams are kept longer than this, they are considered to be too dry and salty, The flavor of the hams is considered satisfactory only after the product has passed through the warm summer season. During this time, the ham will lose about 25-30 per cent of its original weight. The temperature is not controlled during the aging process but there is some control of the humidity by the use of dehumidifiers on damp smer days or by cross ventilation. Preferably, the hams are aged in the dark. During aging, the hams are not handled or permitted to touch each other. There are a number of modifications in processing techniques. In several of the plants visited, the operators expected only a small amount of mold growth on the surface of the hams and considered it desirable to have none. Ordinarily, however, the process resulted in a very heavy mold growth on the flesh side of the ham and, with some processors, presence of these molds is considered an indication of proper curing and aging. Yet, too much mold growth was reported to lead to musty flavor and penetration of the molds through cracks into the interior of the ham. 158. TABLE 1. Number and origin of samples studied. Fermented sausages Country cured hams Country cured bacon No. 43 44 3 U. S. A. 20 Mis souri 13 Mis souri 1 bngary 5 Kentucky 12 Kentucky 1 Italy 5 Iowa 11 Georgia 1 Spain 5 Virginia 4 Holland 2 Tennessee 2 Germany 1 North Carolina 1 Swit z e r land 1 Georgia 1 Greece 1 Rumania 1 Yugoslavia 1 Czechoslovakia 1 Ninety samples of cued and aged meats were tested in this laboratory for characteristic fungal flora. Most of these meats were high quality, gourmand-type products for which fungi are believed to be desirable. The samples analyzed include all major types of cured and aged meats of the U. S. and Europe with which fungi are comnonly associated. In addition, a Yorkshire bacon (England) was examined but was not believed to have a characteristic flora. In all, 670 fungal strains were isolated (456 molds and 214 yeasts). It is believed that the fungi isolated are representative of the yeast and mold flora. This view is supported by the observation that the fungal flora isolated from products obtained from different localities but of the same type, proved to be quite similar. Apparently, cured and aged meats provide a substrate suitable only for certain species of cosmopolitan yeasts and molds. Table ‘2 gives the moisture and fat contents of various sausages. Sausages made in the U. S. were not as dry as those obtained from Europe. Except for those from Italy and Greece, the fat content was similar. These two sausages were quite greasy and had large chunks of fat that had a yellow appearance due to the discolored lipids. Yeasts were found to be more commonly associated with fermented sausages than with country cured hams and were more prevalent on the surface than in the interior of these products. Yeasts were found on the surface of about 2/3 of the hams and 90% of the sausages sampled while they were found in the interior of 1/4 of the hams and 1/2 of the sausages examined. Although yeasts were recovered from high quality products, if they were present in excessive amounts (greater than five million per gram), they contributed to spoilage (Table 3). Salami obtained from Hungary and Holland were characterized by heavy mold growth on the casing of the product while mold growth on genuine Italian salami was somewhat scanty. Yet, sausages from the San Francisco area, although labeled as Italiantype salami, showed heavy mold growth on the surface. 159. TABLE 2. Fat and moisture content of fermented sausages. Per cent moisture Per cent fat* Spain 28.3 58.9 Spain 17.7 46.7 Spain 22.2 25.9 Italy 25.1 73.4 Italy 23.9 44.5 Greece * 18.3 70.2 Yugoslavia* 18.9 55.8 HwarF 20.3 62.5 Rumania** 17.9 55.6 Czechoslovakia* 19.7 59.6 California 32.2 41.6 California 35.0 49.2 * Calculated on dry weight basis ** Somewhat dehydrated during transportation and storage 160.