Panagiota Panagiotaki

A comparative presentation of implementation of ISO 22000 versus HACCP and FMEA in a small size Greek factory producing smoked trout: a case study.

ISO 22000 is the new standard bound to replace HACCP on issues related to food safety. Although several companies, especially the big ones, have either implemented or are on the point of implementing ISO 22000, there are many others which are rather timid and/or reluctant to implement it. The main reason behind that is the lack of information and the fear that the new standard is too demanding in terms of bureaucratic work. This paper aims at making a comparative presentation of how the two systems can be applied to a small smoked salmon producing company thereby facilitating the emergence of the differences. The main difference is that in ISO 22000 systems like Good Manufacturing Practice and Good Hygiene Practice are prerequisites thus leading to lower number of CCPs. In this case study for example, the number of CCPs dropped from eight (8) in HACCP to four (4) in ISO 22000. Furthermore, the Failure Mode and Effect Analysis was applied to the smoked trout manufacturing process in an attempt to calculate quantitatively the Risk Priority Number (RPN) and to find out whether it can be effectively correlated to ISO 22000 and/or HACCP. RPN was found to be higher than 130 for eight steps, in close agreement with HACCP, thereby indicating that corrective actions will have to be undertaken.

Molecular cloning of four glutathione peroxidase (GPx) homologs and expression analysis during stress exposure of the marine teleost Sparus aurata.

Glutathione peroxidase (GPx; EC 1.11.1.9) is an important family of enzymes that protects organisms from oxidative damage. Four full-length GPx cDNAs were cloned and characterized by rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR) from the liver of gilthead sea bream (Sparus aurata), an economically important species for Mediterranean aquaculture. Structural and functional annotations were performed for all paralogs, which suggested possible differences in function and subcellular localization. The phylogenetic analysis, based on the amino acid sequences, revealed four groups corresponding to teleostean GPx1a, GPx1b, GPx4a, and GPx4b and three groups for mammalian GPx1, GPx2 and GPx4. The tree topology indicated past duplication events for fish genes, unlike their mammalian homologs. Transcriptional analysis in ten tissues by reverse transcription quantitative polymerase chain reaction (RT-qPCR) evidenced a tissue-specific pattern for each GPx homolog. Fish experimental groups were exposed to stress factors such as fasting and confinement. Relative expression analysis in fish liver demonstrated that GPx1 genes were not regulated by dietary restriction; GPx4b was differentially expressed opposed to regularly fed fish. On the other hand, both GPx1 and GPx4 genes were up-regulated in fish post exposed to confinement, considered as a response to acute stress. The results underline the role of GPx genes as indicators of stress and welfare status in gilthead sea bream aquaculture.

DNA damage and differential gene expression associated with physical stress in gilthead seabream (Sparus aurata).

Fish stress may result in inhibition of reproduction, development and growth. Thus, appropriate indices should be developed to accurately define the physiological plasticity of fish, in terms of coping with stress. Sea bream individuals were subjected to physical stress (fasting and confinement). DNA fragmentation of liver cells was assessed, in addition to gene expression of selected genes and plasma cortisol levels determination. Stress response was characterized with significant temporal alterations. Increased DNA fragmentation was observed as an aftereffect of physical stress and consequently gene expression of tp53 was stimulated. The expression pattern of glucocorticoid receptor (nr3c1) was directly correlated with plasma cortisol. Furthermore, glucokinase (gk) gene expression was considerably upregulated under acute stress, depicting putative energetic demands. Finally, igf1 downregulation during stress, reflects the suppression of the GH/IGF axis and the substantial stress effects on growth. To conclude, most of the indices described in the present study could be synergistically used, in order to robustly quantify physical stress in marine teleosts.

Identification of the abiotic stress-related transcription in little Neptune grass Cymodocea nodosa with RNA-seq

Seagrasses exhibit vital ecological roles in the marine environment. Nevertheless, the genomic resources available for seagrasses are still scarce. In the present study, the transcriptome of Cymodocea nodosa was sequenced with a view to study the molecular mechanisms underlying abiotic stress responses. The sequenced transcriptome for the species was near-complete and a high percentage of the transcripts was computationally annotated. An experimental simulation of marine plant exposure to extreme temperature (34°C), salinity (50psu) and their combination was conducted. A dynamic transcriptome 24h response (short-term) from stress initialization was recorded. The most noteworthy alteration in gene expression was observed in heat-stressed plants. Transcripts associated with development, photosynthesis, osmotic balance and stress-response were differentially expressed, under the set experimental conditions. Results indicate a potential negative interaction of heat and osmotic stress on seagrasses transcriptome.

Proteins from fish eggs that protect DNA from acid precipitation and inhibit DNA synthesis.

We partially characterized proteins that inhibit DNA acid precipitation from various fish eggs (Sparus aurata, Dicentrarchus labrax, Mugil cephalus and Zeus faber). The active proteins were purified by acetone fractionation. The activity was found to be heat resistant. Of bivalent cations tested only Co(2+) and Cu(2+) exerted a profound promoting effect in the activity from all fish. The protein fraction from Sparus aurata inhibited DNA synthesis in PCR performed by different DNA polymerases. The possible role of DNA protective proteins in fish egg physiology is discussed.