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Abstract

Cold smoked trout (Oncorhynchus mykiss) is a traditional product from the San Daniele del Friuli area (Italy), usually packaged under vacuum, and its shelf life is 60 days. Aim of this study was to evaluate the influence of two different packaging systems (Vacuum packaging-VP and Modified atmosphere packaging-MAP) on the microbial, physico-chemical and sensorial changes of sliced cold smoked rainbow trout during storage. MAP packaged sample showed lower microbial loads than VP packaged sample throughout storage. Microbial count of VP packaged sample exceeded the limit of 6 log CFU/g after 60 days of storage. The total volatile base-nitrogen (TVB-N) values increased over time in both treatments, reaching values close to the limit of 40 mg N/100 g after 45 days. Also TBARS values did not were up to 10 nmol/g in both VP and MAP. The shelf life of 60 days seems to be too long, particularly for the VP samples. A panel composed of 12 nonprofessional assessors perceived significant differences in the sensorial characteristic of the samples, and concluded that the sensorial quality of MAP packaged products were better than the VP ones (P<0.05).

Enhancing storage stability of smoke-flavored horse mackerel filets using natural extracts as preservatives

“…At this juncture, the PBE sample exhibited the highest pH value (6.38 ± 0.03), demonstrating significant differences (p < 0.05) when compared to the Control and MiE samples. This decline in pH values observed in all samples after 15 days of storage (p < 0.05) is likely attributed to the expected increase in activity of lactic acid bacteria, which typically exert a buffering effect on the food substance, as noted by Iacumin et al (2017). Eyo (2001) emphasized that pH indicates the degree of microbial spoilage in fish, noting that some proteolytic microbes produce acid from carbohydrate decomposition, thereby elevating the acidity of the medium.…”

Analysis of the Bioprotective Potential of Different Lactic Acid Bacteria Against Listeria monocytogenes in Cold-Smoked Sea Bass, a New Product Packaged Under Vacuum and Stored at 6 ± 2°C

“…At the established dates, three samples from each group were subjected to microbiological analyses, which included evaluation of the total bacterial count (CBT) in Gelysate agar (gelatine sugar-free agar, Oxoid, Italy) incubated at 30°C for 48-72 h; LAB in deMan Rogosa Sharpe agar (MRS, Oxoid, Italy) incubated at 37°C for 48 h (double layer method); Carnobacterium in TSM agar incubated at 30°C for 2 days under anaerobiosis; yeasts and moulds in malt extract agar (MA, Oxoid, Italy) incubated at 25°C for 72-96 h; total coliforms and faecal coliforms in violet red bile lactose agar (VRBLA, Oxoid, Italy) incubated, respectively, at 37 and 44°C for 24 h; coagulase-positive staphylococci in Baird-Parker agar medium (BP, Oxoid, Italy) with egg yolk tellurite emulsion added (Oxoid, Italy) incubated at 35°C for 24-48 h and confirmed by the coagulase test; sulfite-reducing Clostridia in differential reinforced clostridial medium (DRCM, VWR, United States) incubated at 37°C for 24-48 h in a jar prepared for anaerobic reaction with a gas-packing anaerobic system (BBL, Becton Dickinson, United States); L. monocytogenes detected and quantified according to the ISO method (ISO 11290-1:1996Adm.1:2004 and Salmonella spp. detected and quantified according to the ISO method (ISO 6579-1: 2002Cor.1:2004. To confirm the growth of the starters, five colonies were collected from deMan Rogosa Sharpe plates and TSM agar and then identified by the methods reported in Iacumin et al (2009).…”

“…Consequently, their shelf life is limited to 9-12 days. In fact, within a short time, tissue enzymes and contaminating microbial populations adapt to refrigeration temperatures, producing metabolites typical of spoilage, which consist of basic volatile nitrogen (ammonia compounds), trimethylamine, amines, peroxides, and compounds derived from the degradation of lipids (malonaldehyde; Joffraud et al, 2001;Comi, 2016;Iacumin et al, 2017Iacumin et al, , 2020. Therefore, for trout, salmon and other fish, smoking is increasingly used to extend their shelf lives up to 45-60 days under refrigeration.…”

La trucha (Oncorhynchus mykiss): Potenciales productos alimenticios derivados del principal recurso acuícola en regiones altoandinas

“…La trucha ahumada en frío es un producto tradicional en Italia. Al respecto, Iacumin et al (2017) estudiaron el almacenamiento a 4°C de rodajas de trucha ahumadas en frío, envasadas al vacío (RTEV) y en condiciones de atmósfera modificada (RTEAM), reportando que los valores de TVB-N se incrementaron con el tiempo sin exceder el límite (40 mg N/100 g) luego de transcurrido 45 días; también las concentraciones de TBARS fueron menores a 10 nmol/g, adicionalmente, la conservación del producto y la calidad sensorial fue mayor en las RTEAM que en las RTEV. Por otro lado, Fıcıcılar y Genccelep (2017) estudiaron el ahumado en caliente de trucha.…”