María C. García Fontán

Effect of fat content on physical, microbial, lipid and protein changes during chill storage of foal liver pâté.

The effect of fat content (30%, 35% and 40%) on physical, microbial, lipid and protein changes, during chill storage, of foal liver pâté was studied. Microbial counts showed differences (P<0.05) during storage time and among fat levels. Lightness and redness values gradually decreased over time, while yellowness increased during the whole period and displayed the highest values at the end of storage. The significant increase of protein carbonyls, during chill storage, of foal liver pâté reflects the intense oxidative degradation of the muscle proteins. The fat level presented significant differences in lipid oxidation, since foal pâtés with higher fat content (HF) showed significant higher TBARs values, compared to pâtés with lower fat content (LF) (0.54 vs. 0.46 mg MDA/kg pâtés; P<0.001). Finally, NHI (non heme iron) increased during refrigerated storage of foal liver pâté, with the contents in the HF group being higher at all stages of storage (P<0.05).

Study of the lactic acid bacteria throughout the manufacture of dry-cured lacón (a Spanish traditional meat product). Effect of some additives.

Total aerobic mesophilic microflora (on SPC agar), lactic acid bacteria (on MRS agar) and lactobacilli (on Rogosa agar) were enumerated in samples from the surface and the interior of the pieces throughout the manufacture of six batches of lacón. Three of the batches were made without additives and three with additives (glucose (2 g/kg), sodium nitrite (E(250)) (125 mg/kg), sodium nitrate (E(251)) (175 mg/kg), sodium ascorbate (E(301)) (500 mg/kg), and sodium citrate (E(331)) (100 mg/kg)). The counts decreased throughout the manufacturing process, particularly after the salting stage. The use of additives did not affect the counts or the evolution of the microbial groups, except for the lactobacilli, which were present in higher numbers in the batches with additives. In four batches (two without and two with additives), from MRS agar and from Rogosa agar plates, 10 colonies were randomly taken from each sampling point of each batch (five from the surface sample and five from the interior sample) and from each culture medium; a total of 224 strains from MRS agar, and 176 strains from Rogosa agar that were identified by classical methods. The MRS agar displayed moderate selectivity for the isolation of lactic acid bacteria, and only 59% of the isolated strains belonged to this microbial group. Homofermentative and facultative heterofermentative lactobacilli (particularly Lactobacillus curvatus and Lactobacillus sakei) were the most abundant species isolated on this medium. The selectivity of the Rogosa agar for lactobacilli was extremely high. The species of lactobacilli isolated on this medium at different stages of manufacture of the four batches of lacón were consistent with those isolated from MRS agar. The use of additives in the lacón did not appreciably affect the kinds and proportions of species isolated on either MRS agar or Rogosa agar.