RESUMEN
Lipid oxidation and proteolysis are essential processes in Serrano dry-cured ham quality. The influence of high pressure processing (HPP) at 600â¯MPa for 6â¯min on lipid oxidation, aminopeptidase (AP) activities and free amino acids (FAA) in ripened Serrano hams of different chemical composition after 5â¯months at 4⯰C were studied. HPP increased lipid peroxidation indexes. Composition influenced both indexes, with higher levels in hams of medium or high intramuscular fat (IMF) content and in hams of low or medium salt content or salt-in-lean ratio. HPP lowered AP activities by more than 50%. Composition also affected AP activities, with lower levels in hams of low aw, high IMF content, low salt content or low salt-in-lean ratio. At the end of refrigerated storage, HPP only affected Arg and Tyr levels. Many of the individual FAA reached higher levels in hams of low aw, medium or high IMF content, low or medium salt content, or low or medium salt-in-lean ratio.
Asunto(s)
Manipulación de Alimentos/métodos , Productos de la Carne/análisis , Tejido Adiposo , Aminoácidos/análisis , Aminopeptidasas/análisis , Animales , Conservación de Alimentos/métodos , Peroxidación de Lípido , Presión , Cloruro de Sodio , Sus scrofaRESUMEN
The efficacy of pulsed light (PL) for the surface decontamination of ready-to-eat dry-cured ham was studied in two Spanish varieties, Serrano and Iberian. Listeriainnocua was inoculated on the surface of ham slices that were vacuum-packaged and flashed with 2.1, 4.2 and 8.4 J/cm2. Survivors were enumerated immediately after treatment. Peroxide values, sensory analysis and volatile profile were investigated during storage at 4 and 20 °C. Inactivation of Listeria was higher in Iberian (ca. 2 log cfu/cm2) than in Serrano ham (ca. 1 log cfu/cm2) with 8.4 J/cm2. PL did not increase the peroxide values above the usual levels reported in dry-cured ham, and no rancid notes were observed in the sensory analysis. PL-treated samples showed an increase in the concentration of some volatile compounds, such as methional, dimethyl disulfide and 1-octen-3-one, which imparted slight sulfur and metallic notes, although they disappeared during storage.
Asunto(s)
Listeria/aislamiento & purificación , Productos de la Carne/análisis , Animales , Embalaje de Alimentos , Conservación de Alimentos , Luz , Oxidación-Reducción , Carne de Cerdo , Porcinos , VacioRESUMEN
The effect of Serrano and Iberian dry-cured ham processing and ripening on Listeria monocytogenes inactivation at the surface of whole hams was investigated. Salted hams were surface inoculated (6.5 log CFU) with a cocktail of 4 L. monocytogenes strains isolated from environment and products of a meat industry. Serrano and Iberian hams were ripened for 16 and 24 months, respectively. A decrease of at least 4.6 log units on the surface of Serrano ham was recorded after 4 months for L. monocytogenes counts, which remained under the detection limit thereafter. L. monocytogenes declined by >5 log units on the surface of Iberian ham during the first 9 months and was not detected afterwards. The higher nitrite content of Serrano ham might have accelerated the decrease of the pathogen. This study validates the inactivation of L. monocytogenes on the surface of whole dry-hams during extended ripening.
Asunto(s)
Microbiología de Alimentos , Conservación de Alimentos/métodos , Listeria monocytogenes/aislamiento & purificación , Productos de la Carne/microbiología , Carne de Cerdo/microbiología , Animales , Recuento de Colonia Microbiana , Productos de la Carne/análisis , Nitritos/análisis , Carne de Cerdo/análisis , Porcinos , Factores de TiempoRESUMEN
The microbiota of Serrano dry-cured ham of different chemical composition, subjected or not to high-pressure processing (HPP), was investigated using culture-dependent and culture-independent methods. Microbial counts were submitted to analysis of variance with physicochemical parameters (aw, NaCl concentration, salt-in-lean ratio and intramuscular fat content) or HPP as main effects. In untreated hams, physicochemical parameters significantly affected counts of aerobic mesophiles, psychrotrophs, and moulds and yeasts. NaCl concentration and fat content influenced the levels of four and three of the five studied microbial groups, respectively, whereas no influence of aw was stated. The HPP treatment had a significant effect on counts of all investigated microbial groups. Culture-independent methods showed the presence of bacteria such as Staphylococcus equorum, Staphylococcus succinus, Bacillus subtilis and Cellulosimicrobium sp., moulds like Penicillium commune, Aspergillus fumigatus, Sclerotinia sclerotiorum, Eurotium athecium and Moniliella mellis, and yeasts like Debaryomyces hansenii and Candida glucosophila. Absence of B. subtilis bands and weaker bands of E. athecium were recorded for HPP-treated hams. The higher microbial levels found in lean ham might result in a quicker deterioration. HPP treatment confirmed its suitability as a procedure to control spoilage microorganisms. DGGE did not seem to be sensitive enough to highlight changes caused by HPP treatment in the microbiota of ham, but contributed to the detection of microbial species not previously found in ham.
Asunto(s)
Bacterias/aislamiento & purificación , Conservación de Alimentos/métodos , Hongos/aislamiento & purificación , Productos de la Carne/microbiología , Microbiota , Animales , Bacterias/genética , Bacterias/crecimiento & desarrollo , Manipulación de Alimentos , Conservación de Alimentos/instrumentación , Hongos/genética , Hongos/crecimiento & desarrollo , Productos de la Carne/análisis , Presión , Cloruro de Sodio/análisis , PorcinosRESUMEN
"Serrano" ham is a typical pork product from the Mediterranean area, highly valued for its flavour. To make Serrano ham, pork undergoes a salting and a subsequent fermentation process known as curing. Certain pigs used for meat production are an important source of Toxoplasma gondii infection in humans. We have developed a method for quantifying and assaying the viability of the T. gondii present in commercial Serrano ham samples. A magnetic capture method for the isolation of T. gondii DNA and a qRT-PCR were used to estimate the T. gondii burden in 475 commercial samples of "Serrano" ham in two presentation formats: ham pieces and sliced ham. The infectivity capacity of T. gondii in positive samples was assayed in mice. The global prevalence of T. gondii was 8.84%, ranging from 32.35% in one of the companies to 0% prevalence in three other companies. The infectivity assays revealed that only 4.84% of the positive samples were infective. To the best of our knowledge this is the first report focussing on the prevalence of T. gondii in commercial "Serrano" ham. The method described here could be useful for producers to guarantee the safety of their products.