H. W. Ockerman1 *, F. León Crespo2, H. Galan Solvedilla2,
A. Peralta Fernandez2, N. Ciudad Gonzalez2, B. Balderas
Zubeldia2, F. Cespedes Sanchez2, A. Martin Serrano2,
and M. C. Torres Munoz2
1The Ohio State University Department of Animal Sciences
2University of Córdoba, Spain
Dry-cured ham fungal flora is primarily composed of strains of the genus Penicillium. Twenty-two strains of this genus were evaluated under different conditions of temperature and relative humidity for their positive influence on flavor. The results indicated that two strains of P. chrysogenum, two strains of P. camemberti, and one strain of P. aurantiogriseum had a positive influence under all tested conditions. The best results from the technological point of view were obtained using P. camemberti and P. aurantiogriseum at low temperatures (3-8°C).
Improving the technological basis for Spanish ham (jamón) production is a very important goal as this product is of high economic value to the meat-processing industry. One of the steps that influence the quality of jamón is the final aging of hams in a bodega, a traditional place, usually underground, very similar to wine cellars. During aging in the bodega, the jamón surface is usually covered by molds, a specific strain for each processing area.
A total of 40 hams from different geographical areas, which included most of the commercial jamón production in Spain, were analyzed and evaluated for types of mold, their influence on ham flavor, and the influence of temperature and humidity on the mold properties.
This study concludes that the fungal flora is mainly composed of strains of the genus Penicillium. These results corroborate previous results of Rojas, 1994; Trigueros et al., 1995; and Toledo et al., 1997. Meat research workers Leistner and Ayres (1968), Leistner (1986), and Krotje (1992) reported that specific mold groups have a positive influence on the flavor development in meat products.
In this study, 22 isolated strains from the genus Penicillium that presented initial morphological differences were tested under different conditions of temperature and relative humidity for their positive influence on flavor. The initial results indicated that two strains of P. chrysogenum, two of P. camemberti, and one of P. aurantiogriseum have a positive influence on meat-product flavor under all of the tested combinations of temperature and relative humidity. These species have been isolated previously from meat products by Vayssier (1979), Huerta et al. (1987), and Rojas (1994).
This research also included a further metabolic study of the selected strains under different conditions of temperature and relative humidity. This was an attempt to obtain objective results in order to optimize the use of these microbial strains as starters in meat production.
The five selected strains have been studied for their influence on flavor in a model meat system (ground meat with 10% salt in the water phase added) simulating the surface of jamón during the bodega aging step. The study included changes in pH, NPN, free amino acids, ammonia N, acidity index of fat, peroxide index, and TBA index. The study also included monitoring the growth of bacterial populations (total microbial count and micrococci).
After analyzing the effects of conditions tested, it has been shown that time of incubation, inoculated strains, relative humidity, and temperature, as well as the interaction of most of these conditions, influenced the observed changes in the organoleptic and chemical studied parameters.
The best results from the technological point of view were obtained using P. camemberti and P. aurantiogriseum at low temperatures (3 to 8ºC).
Huerta, T., Sanchis, V., Hernández, J., and Hernández, E. (1987). Mycoflora Mycrobiologie-Aliments-Nutrition. 5: 247—252.
Krotje, D. 1992. International Food Ingredients 6:14—18.
Leistner, L. 1986. Mould ripened foods. Fleischwirtsch 66:1385—1388.
Leistner, L. and Ayres, J. C. 1968. Molds and meats. Die Fleischwirtschaft 48:62.
Rojas, F. J. 1994. Evolución de la Flora Fúngica del Jamón Curado Durante su Elaboración: Influencia de los Conservadores. Ph.D. Dissertation. Dpto Bromatología y Tecnología de Alimentos. Fac. Veterinaria. Univ. Córdoba, Spain.
Toledo, V. M., Selgas, M. D., Casas, M. C., Ordóñez, J. A., García, M. L. 1997. Food Research and Technology 204(5):385—390.
Trigueros, G., García, M. L., Ordóñez, J. A., y Selgas, M. D. 1995. Z. Lebensm. Unters. Forsch. 201:298—302.
Vayssier, Y. 1979. Microbial "fl. RTVA 18: 139.
* Collaborative research with the University of Córdoba
1 For more information, contact at: The Ohio State University 15 Animal
Science, 2029 Fyffe Road, Columbus, OH 43210, (614) 292-4317, Fax (614) 292-2929;
email:ockerman.2@osu.edu