Incidencia de histamina y de bacterias indicadoras de calidad higiénica, en filetes, ruedas y trozos de pescado de especies pelágicas comercializadas en un mercado de pescado de la isla de Margarita (Venezuela) / Incidence histamine and hygienic quality indicators´s bacteria in fillets, slice and pieces pelagic fish´s marketing in one fish´s market of Margarita´s Island (Venezuela)

Se estudió la incidencia de histamina y de bacterias indicadoras de manejo higiénico en filetes, ruedas y trozos de diez especies de pescado en estado fresco, (Euthynnus alletteratus; Caranx latus; Ophisthonema oglinum; Alectis crinitus; Sardinella aurita; Thunnus alalunga; Sarda sarda; Scomberomorus cavalla; Coryphaena hippurus y Xyphias gladius), comercializadas en un mercado de pescado de Isla de Margarita (Venezuela). Según normas COVENIN se enumeraron (UFC g-1) aerobios a 25 y 32 °C, coliformes fecales y Escherichia coli (NMP g-1); histamina (mg/100 g) y pH. También recuentos (UFC g-1) de enterobacterias (ICMSF) y bacterias descarboxiladoras de histidina (Niven y otros). Todos los recuentos de aerobios a 25 °C excedieron el valor m (Log10 = 5,70 UFC g-1) fijado por ICMSF (1986). La prueba r de Pearson indicó que los recuentos a 25 y 32 °C estuvieron altamente relacionados (n = 90; r = 0,89; p < 0,01). E. coli superó en el 76% de las muestras el valor m (Log10 = 1,04 NMP g-1). Las mayores cifras de histamina se detectaron en T. alalunga (promedio 43,5 mg/100 g en uno de tres muestreos); seguido por S. aurita (promedios de 23,7 y 28,0 mg/100 g respectivamente, en dos muestreos). Sólo en muestras de T. alalunga se detectaron olores penetrantes y músculos con elasticidad disminuida. Estos datos y la observación de factores adversos, tales como contacto directo con superficies y utensilios sucios, restos de vísceras, desangrado deficiente, presencia de insectos, utilización de agua no potable y la exposición a temperaturas no apropiadas, reflejan que la manipulación del pescado no fue adecuada. Se recomienda que inspectores sanitarios implementen acciones tendentes a corregir estas deficiencias.

The incidence of histamine and of bacteria that indicate hygienic handling of fillets, slices and pieces of ten pelagic fresh fish (Euthynnus alletteratus; Caranx latus; Ophisthonema oglinum; Alectis crinitus; Sardinella aurita; Thunnus alalunga; Sarda sarda; Scomberomorus cavalla; Coryphaena hippurus and Xyphias gladius), sold in a fish market at Margarita Island (Venezuela) was assessed. According to COVENIN´s norms, total aerobic plate count (FCU g-1) at 25 and 32 °C; fecal coliforms and Escherichia coli (MPN g-1); histamine (mg/100 g) and pH were measured. Also, members of the Enterobacteriaceae family (FCU g-1) and histamine producing bacteria were counted, according to ICMSF and Niven et al respectively. All total aerobic plate count at 25 °C surpassed the m number (Log10 = 5.70 CFU g-1) established by ICMSF (1986). The Pearson test (r) showed that bacteria total counts at 25 and 32 °C were highly related (n = 90; r = 0.89; p < 0.01). E. coli exceeded in 76% of samples the number (Log10 = 1.04 MPN g-1). Histamine biggest numbers were detected in T. alalunga (average 43.5 mg/100 g in one of three samplings), followed by S. aurita (averages of 23.7 and 28.0 mg/100 g respectively, in two samplings). Only in T. alalunga samples were penetrating odors detected and muscles with reduced elasticity. This data and the adverse factors observed, such as: fish in direct contact with dirty areas and utensils, leftover viscera, faulty bleeding, presence of insects, use of non potable water and the exposition of fish at inappropriate temperatures, revealed the handling of fish was not suitable. It is recommended that sanitary officers carry out actions necessary to correct these deficiencies.

Application of sensory and microbial analysis to assess quality of fish in Siliguri city of West Bengal, India.

Sensory and certain microbial analyses were applied to assess the quality of raw fish sold at a market in Siliguri city of West Bengal, India. In regular surveys undertaken during June to August 2008, a particular fish species was randomly selected, its source was noted and a sensory analysis, the quality index method (QIM) was applied to assess its quality. Raw fish samples were also collected and a small quantity (about 1 g) of scales or an upper layer of the skin surface (for scale-less fish samples), gill, liver and a portion of gut with gut-contents were aseptically removed for enumeration of the total aerobic heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and coliform counts. Oreochromis mossambicus and Tenulosa ilisha recorded significantly higher QIM scores, compared to other species (p<0.05). Riverine fish, Lepidocephalichthys guntea and Channa punctatus scored the lowest QIM scores (0) while scores for Puntius ticto and Mystus vittatus and pond cultured species like Cirrhinus mrigala, Catla catla, Labeo rohita, Labeo bata and Cyprinus carpio were very marginal (p<0.05). Aeromonas spp., Salmonella spp. and total coliforms were recorded from all the studied species while Pseudomonas spp. was isolated from only seven species. Among the tissues examined, the lowest counts of total heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and total coliforms were recorded from the skin in every fish species. Highest counts of pathogenic bacteria (except Pseudomonas spp.) were recorded in Tenulosa ilisha for all the tissues except liver. Since fish are properly cooked in Bengali households, the risk of disease from fish consumption is relatively less. However, some tribes residing in the region are known to consume undercooked fish and proper cooking methods should be followed in view of the present findings to avoid health risks. Besides, utmost care should be taken while handling fish.