Abstract The present study assessed the effect of incorporating essential oil of oregano (EOO) and oregano bagasse (OB) into the diet on the productive parameters and on the variables sacrifice and quality of rabbit meat. A total of 100 rabbits (30 d of age) were distributed in six treatments T1: control, T2: 0.25 g/kg of EOO, T3: 0.40 g/kg of EOO, T4: 20% of OB, T5: 0.25 g/kg of EOO + 20% of OB, and T6: 0.40 g/kg of EOO + 20% of OB. The greatest live weight was that of T6 (P˂0.0001). At d 37, 44 and 51, T3 exhibited the lowest food intake (P=0.0089), and T6 had the best weight gain (P=0.0172). Food conversion was best (P=0.0138) in T5 at d 37. The yield of the cold carcass and loin was highest in T2, T4 and T5 (P<0,001). The pH increased (P=0.0190) at 10 d post mortem in T1, T4, T5, and T6. The water retention capacity was greater (P=0.0500) in T2, T4, and T6; a* increased (P<0.0004) on d 10 post mortem, and b* was lower (P<0.0430) in T2 at 24 h and 1at 0 d post mortem. In conclusion, 0.25 and 0.40 g/kg of EOO with 20% of OB had a positive influence on the productive behavior and on the variables slaughter, carcass characteristics, and quality of rabbit meat.

Resumen Se evaluó el efecto del aceite esencial de orégano (AEO) y bagazo de orégano (BO) incorporados en la dieta sobre los parámetros productivos, variables de sacrificio y calidad de la carne de conejos. Un total de 100 conejos (30 d de edad) fueron distribuidos en seis tratamientos T1: control, T2: 0.25 g/kg de AEO, T3: 0.40 g/kg de AEO, T4: 20% de BO, T5: 0.25 g/kg de AEO + 20% de BO y T6: 0.40 g / kg de AE + 20% d-e BO. El mayor peso vivo fue el T6 (P˂0.0001). En 37, 44 y 51 días, T3 presentó el menor consumo de alimento (P=0.0089) y T6 tuvo la mejor ganancia de peso (P=0.0172). La conversión alimenticia fue mejor (P=0.0138) en T5 a los 37 días. El rendimiento de la canal fría y lomo fue más alto en T2, T4 y T5 (P<0.001). El pH incrementó (P=0.0190) en 10 días post mortem para T1, T4, T5 y T6. La capacidad de retención de agua fue mayor (P=0.0500) en T2, T4 y T6; a* aumentó (P<0.0004) en el día 10 post mortem, y b* fue menor (P˂0.0430) en T2 a 24 h y 10 días post mortem. En conclusión, 0.25 y 0.40 g/kg de AEO con 20% de BO influyeron positivamente en el comportamiento productivo, variables de sacrificio, características de la canal y calidad de la carne de conejo.

Abstract Microbial quality and the prevalence of foodborne pathogens (E. coli 0157:H7, Salmonella spp., Listeria monocytogenes and Campylobacter jejuni) of cheeses sold at three retail points (supermarkets [SM], street markets [ST], and convenience grocery stores [CGS]) in Chihuahua, Mexico, were evaluated (n=90). The most commonly found cheeses in the retail points were Chihuahua (60%) and Ranchero (28.8%). According to Mexican standards, three SM, two CGS, and none of the ST cheeses complied with the regulations. Two cheeses (cheddar and Ranchero) from SM (2.22%) were positive for L. monocytogenes. Eight cheeses (8.88%) were positive for Salmonella spp. (5 from ST and 3 from CGS). E.coli 0157:H7 and Campylobacter jejuni were negative in all samples. In the Ranchero cheese, total coliforms (TC), faecal coliforms (FC), and yeast and moulds (Y&M) showed no significant differences (P > 0.05) among retail points. Nevertheless, in Chihuahua cheese, the numbers of total coliforms, faecal coliforms, and yeast and moulds were statistically different (P < 0.05) among retail points. PSM Chihuahua cheese had the lowest numbers of total (0.99 ± 1.0 Log10CFU/g) and faecal coliforms (166 ± 154 Log10CFU/g). CGS cheeses had the lowest counts in terms of yeast and moulds (3.1 ± 2.2 Log10CFU/g). The results revealed that most cheeses, regardless of the retail point, did not conform to Mexican standards. The number of total and faecal coliforms indicates either flaws during the production and commercialization processes or the ill-handling of raw materials.

Abstract The aim of this work is to characterize the natural microflora of artisanal Ranchero cheese and to identify Lactococcus isolates. Ten artisanal Ranchero cheese samples made with raw milk were obtained from local producers located in different geographical areas. Aerobic mesophilic, Staphylococci, Psychrophilic , total coliforms, molds, yeast and, lactic acid bacteria (LAB) (Lactococcus , Streptococcus mesophilic and thermophilic, Lactobacillus , Enterococcus, Leuconostoc) were numbered through agar plating. LAB isolates were classified by genus. Then, nineteen randomly selected presumptive Lactococcus isolates were assigned to specie by PCR amplification and DNA sequence. A high number of aerobic mesophilic Staphylococci, Psychrophilic, total coliforms, molds, and yeast were found. Lactococci, mesophilic and thermophilic Streptococci and Lactobacilli were the dominant LAB. Enterococci and Leuconostoc were also present. The isolates were identified as L. lactis subsp. lactis and L. garvieae . And both were found to be the dominant Lactococcus species that could be selected and used in a starter culture. Sanitation deficiencies in the production of artisanal Ranchero cheese were evident, which may translate into being a potential consumers health risk factor.

Milk and dairy products are sources of highly valuable biological proteins. Some of these have biological, nutritional and functional activities in humans. In recent years, it has been reported that peptides derived from milk proteins, are able to positively influence the health of consumers. However, they do not exert any benefit beyond the contribution of nutrition when they are part of the native milk proteins, so it is necessary to subject proteins to enzymatic hydrolysis. This process can be carried out by the native milk microorganisms or by those who are inoculated during processing and by the addition of commercial enzymes during processing. Note that the hydrolytic effect is not limited to the production of dairy products, but it continues during ripening and shelf life. Also, several studies have shown that the activity of gastrointestinal enzymes is determinant in undergoing hydrolysis of milk proteins. Such that the release of the peptide, coupled the size, hydrophobicity and sequence are prerequisites to become biologically active peptides. The latter, also considered as bioactive peptides or biopeptides have recently attracted the interest of researchers because they can favorably influence the functions carried out by the immune, gastrointestinal, nervous and cardiovascular systems hence impacting the health of consumers. In this review the mechanisms by which the bioactive peptides derived from milk proteins are generated and the physiological effects the produced where addresed.

La leche y los productos lácteos son fuente de proteínas de alto valor biológico. Algunas de éstas presentan actividades biológicas, nutricionales y funcionales en el ser humano. En los últimos años se ha reportado que los péptidos, derivados de las proteínas lácteas, son capaces de influir positivamente en la salud del consumidor. Sin embargo, éstos no ejercen beneficio alguno, más allá del aporte nutricional, cuando forman parte de las proteínas lácteas nativas, por lo que es necesario someter a las proteínas a procesos de hidrólisis enzimática. Este proceso puede llevarse a cabo por los microorganismos propios de la leche o por aquellos que son inoculados durante la elaboración y por la adición de enzimas comerciales utilizadas durante el procesado. Cabe señalar que el efecto hidrolítico no se limita a la elaboración de los productos lácteos, sino que continúa durante la maduración y la vida en el anaquel. Así mismo, diversas investigaciones han evidenciado que la actividad de las enzimas gastrointestinales es determinante en la hidrólisis que experimentan las proteínas lácteas. De tal forma que la liberación de los péptidos, aunada al tamaño, hidrofobicidad y secuencia de los mismos constituyen requisitos indispensables para convertirlos en péptidos con actividad biológica. Éstos últimos, también considerados como péptidos bioactivos o biopéptidos, han despertado recientemente el interés de los investigadores debido a que pueden influenciar favorablemente las funciones que llevan a cabo los sistemas inmune, gastrointestinal, nervioso y cardiovascular impactando la salud del consumidor. En esta revisión de literatura, se abordaron los mecanismos por los cuales son generados los biopéptidos derivados de proteínas lácteas y los efectos fisiológicos que producen.

Three different origin rainbow trout varieties were used to determine the variability of their carcass and meat quality; were used 80 Danish, 80 American and 80 Mexican, at different weight intervals; 175 -224 g (I1), 225 -274 g (I2), 275 - 324 g (I3) and 325 - 374 g (I4). Results indicated that Mexican trout had better carcass yields 88.35% at I3 and 87.34% at I4. For meat quality American trout at I2 had highest pH (7.14) and at I3 the highest luminosity value 47.53, the Danish at I2 had the highest water retention capacity 54.65%, this variety also has better protein content 21.58% at I4 and the lowest fat content (2.48%) at I2. Based in these results could be concluded that, Mexican trout due to their high carcass yield must be marketed at I3 or I4 weight ranges. That American trout could be used for filet marketing at I4 and that Danish trout had better qualifications in meat quality for processing.

Para determinar la calidad de canal y carne de tres variedades de trucha arco iris, se emplearon 240 peces (Danesa, 80; Americana, 80 y Mexicana, 80), en cuatro intervalos de peso: 175 - 224 g (I1), 225 - 274 g (I2), 275 - 324 g (I3) y 325 - 375 g (I4). Los resultados indican que los mayores rendimientos de canal se dieron en la variedad mexicana en los I3 (88.35%) y I4 (87.34%). El valor máximo de rendimiento de filete se obtuvo en el I4 (54.67%) de la variedad americana. En la calidad de la carne, la variedad americana presentó el mayor pH en I2 (7.14). La danesa presentó los porcentajes más elevados de capacidad de retención de agua en el I2 (54.65%). Los mayores valores de luminosidad fueron para la trucha de la variedad americana en I3 (47.53). La danesa presentó el valor más alto de proteína cruda en I4 (21.58%) y el valor más bajo de grasa en el I2 (2.48%). Se concluye que por el alto rendimiento en canal la variedad mexicana puede comercializarse en los intervalos de de peso 3 y 4. Por su mayor rendimiento en filete se recomienda sacrificar las truchas de origen americano en el I4. Por otra parte las características de calidad de la carne como el pH, color y capacidad de retención de agua, indican que las danesas tienen mejores cualidades para su procesamiento.