Impact of gelatin nanogel coating containing thymol and nisin on the microbial quality of rainbow trout fillets and the inoculated Listeria monocytogenes

2021 ◽  
Author(s):  
Fatemeh Mohajer ◽  
Saeid Khanzadi ◽  
Kobra Keykhosravy ◽  
Seyyed Mohammad Ali Noori ◽  
Mohammad Azizzadeh ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Listeria Monocytogenes ◽  
Microbial Quality

Pasteurization of Rainbow Trout Roe: Listeria monocytogenes and Sensory Analyses

2005 ◽  
Vol 68 (8) ◽  
pp. 1641-1647 ◽  
Author(s):  
HANNA MIETTINEN ◽  
ANNE ARVOLA ◽  
GUN WIRTANEN
Keyword(s):  
Rainbow Trout ◽  
Listeria Monocytogenes ◽  
Sensory Quality ◽  
Pilot Scale ◽  
Microbial Quality ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Sensory Analyses ◽  
Z Value ◽  
Spore Forming Bacteria

D- and z-values for a mixture of four Listeria monocytogenes strains originating from the roe of different fish species were determined in rainbow trout (Oncorhynchus mykiss) roe. The D60- and D63-values obtained were 1.60 and 0.44 min, respectively, and the z-value was 5.36°C accordingly. In pilot-scale experiments, rainbow trout roe (100 g) was vacuum packaged into glass jars and pasteurized both at 62 and 65°C for 10 min. These treatments were enough to destroy 108 CFU/g of L. monocytogenes cells, which was the highest possible Listeria cell count to grow in roe. On the basis of the determined z-value and calculation of pasteurization values, these experimental pasteurizations were found to theoretically destroy at least 45 log units of L. monocytogenes cells in rainbow trout roe. In addition, these pasteurization treatments did not significantly affect the sensory quality of the roe. The sensory quality of pasteurized vacuum-packaged rainbow trout roe stored at 3°C was evaluated as good after 6 months of storage and not statistically different from the control that was frozen from the same roe lot as the pasteurized roe samples. Pasteurization of rainbow trout roe was proven to be an appropriate method for ensuring product safety with regard to L. monocytogenes and to stabilizing the sensory and microbial quality of roe. However, the safety risk caused by spore-forming bacteria still exists in pasteurized roe. Therefore, it has to be stored below 3°C.

Prevalence of Listeria monocytogenes in, and Microbiological and Sensory Quality of, Rainbow Trout, White fish, and Vendace Roes from Finnish Retail Markets

2003 ◽  
Vol 66 (10) ◽  
pp. 1832-1839 ◽  
Author(s):  
HANNA MIETTINEN ◽  
ANNE ARVOLA ◽  
TIINA LUOMA ◽  
GUN WIRTANEN
Keyword(s):  
Rainbow Trout ◽  
Listeria Monocytogenes ◽  
Sensory Quality ◽  
Heterotrophic Bacteria ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Coregonus Lavaretus ◽  
Retail Markets ◽  
Sensory Qualities

The prevalence of Listeria monocytogenes in retail roe, as well as the microbiological and sensory qualities of the roe, were studied for three fish species under three different storage conditions. A total of 147 Finnish rainbow trout (Oncorhynchus mykiss), white fish (Coregonus lavaretus), vendace (Coregonus albula), and burbot (Lota lota) roe samples were bought fresh, frozen, or frozen-thawed from Finnish retail markets. The overall prevalence of L. monocytogenes was 5%; however, the prevalence of the pathogen in fresh roe was 18%. Fresh-bought roe tested positive for Listeria spp. and for L. monocytogenes, respectively, 5 and 20 times as often as did frozen and frozen-thawed roe products combined. The microbiological quality (analyzed as total aerobic heterotrophic bacteria and coliform bacteria) of 78% of the roe samples was unacceptable. Frozen roe samples were found to have the best microbiological quality. According to the results of a sensory evaluation, at least one sensory attribute (appearance, odor freshness, texture, and freshness of taste) was unacceptable for 29% of the roe samples studied. The sensory quality of roe samples bought fresh was better than that of roe samples bought frozen or frozen-thawed. From the results of this study, it is concluded that both the microbiological and the sensory qualities of roe at the retail level need to be improved.

Effects of Thawing Methods on Chemical, Biochemical, and Microbial Quality of Frozen Whole Rainbow Trout (Oncorhynchus mykiss)

2013 ◽  
Vol 22 (2) ◽  
pp. 168-177 ◽  
Author(s):  
Seyed Rohollah Javadian ◽  
Masoud Rezaei ◽  
Mahdi Soltani ◽  
Mohammad Kazemian ◽  
Reza Pourgholam
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Microbial Quality ◽  
Rainbow Trout Oncorhynchus Mykiss

Microbial Quality of Human Wastes and Treatment Plant Effluent

1986 ◽  
Vol 18 (7-8) ◽  
pp. 257-265 ◽  
Author(s):  
K. Kawamura ◽  
M. Kaneko
Keyword(s):  
Staphylococcus Aureus ◽  
Vibrio Cholerae ◽  
Treatment Plant ◽  
Microbial Quality ◽  
Chlorination Process ◽  
Fecal Streptococci ◽  
Human Wastes ◽  
Micro Organisms ◽  
Spore Forming Bacteria

In order to evaluate the microbial quality of human wastes and effluents from treatment processes, the microbial flora of samples was examined. Total coliforms, fecal coliforms and fecal streptococci were used as indicator micro-organisms, and Vibrio cholerae non O-1, Salmonella, Staphylococcus aureus and Welchii (Clostridium perfrigens) were selected as pathogenic organisms. Salmonella was detected in only the water samples from the night soil treatment plant, while Staphylococcus aureus was detected in the night soil and the samples from the night soil purification tanks. Vibrio cholerae non 0-1 was not detected in any samples, but Welchii existed in almost all samples. Generally, the density levels and distribution patterns of the indicator micro-organisms were similar to those in the raw wastewaters. The microbial flora was not changed remarkably after the primary sedimentation process and the biological treatment process. After the chlorination process, total colonies, spore-forming bacteria, Welchii, moulds and fecal streptococci could survive, and spore-forming bacteria formed the majority of the total colonies in the well-chlorinated effluents. Welchii at the level of 103/100 ml can be used as the indicator micro-organism to ensure a sanitary safe discharge, because it can survive at the level of 103−104/100 ml even if other indicators and pathogenic micro-organisms are inactivated completely by the chlorination process.

scholarly journals Comparisons among rainbow trout, Oncorhynchus mykiss, populations of maternal transcript profile associated with egg viability

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gregory M. Weber ◽  
Jill Birkett ◽  
Kyle Martin ◽  
Doug Dixon ◽  
Guangtu Gao ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Egg Quality ◽  
Transcript Abundance ◽  
Differentially Expressed ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Analysis Group ◽  
Maternal Transcripts ◽  
Single Batch ◽  
Insight Into

Abstract Background Transcription is arrested in the late stage oocyte and therefore the maternal transcriptome stored in the oocyte provides nearly all the mRNA required for oocyte maturation, fertilization, and early cleavage of the embryo. The transcriptome of the unfertilized egg, therefore, has potential to provide markers for predictors of egg quality and diagnosing problems with embryo production encountered by fish hatcheries. Although levels of specific transcripts have been shown to associate with measures of egg quality, these differentially expressed genes (DEGs) have not been consistent among studies. The present study compares differences in select transcripts among unfertilized rainbow trout eggs of different quality based on eyeing rate, among 2 year classes of the same line (A1, A2) and a population from a different hatchery (B). The study compared 65 transcripts previously reported to be differentially expressed with egg quality in rainbow trout. Results There were 32 transcripts identified as DEGs among the three groups by regression analysis. Group A1 had the most DEGs, 26; A2 had 15, 14 of which were shared with A1; and B had 12, 7 of which overlapped with A1 or A2. Six transcripts were found in all three groups, dcaf11, impa2, mrpl39_like, senp7, tfip11 and uchl1. Conclusions Our results confirmed maternal transcripts found to be differentially expressed between low- and high-quality eggs in one population of rainbow trout can often be found to overlap with DEGs in other populations. The transcripts differentially expressed with egg quality remain consistent among year classes of the same line. Greater similarity in dysregulated transcripts within year classes of the same line than among lines suggests patterns of transcriptome dysregulation may provide insight into causes of decreased viability within a hatchery population. Although many DEGs were identified, for each of the genes there is considerable variability in transcript abundance among eggs of similar quality and low correlations between transcript abundance and eyeing rate, making it highly improbable to predict the quality of a single batch of eggs based on transcript abundance of just a few genes.

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