Sample Preservation Research Articles

SARS-CoV-2 RNA Recovery from Air Sampled on Quartz Fiber Filters: A Matter of Sample Preservation?

The airborne route of transmission of SARS-CoV-2 was confirmed by the World Health Organization in April 2021. There is an urge to establish standardized protocols for assessing the concentration of SARS-CoV-2 RNA in air samples to support risk assessment, especially in indoor environments. Debates on the airborne transmission route of SARS-CoV-2 have been complicated because, among the studies testing the presence of the virus in the air, the percentage of positive samples has often been very low. In the present study, we report preliminary results on a study for the evaluation of parameters that can influence SARS-CoV-2 RNA recovery from quartz fiber filters spotted either by standard single-stranded SARS-CoV-2 RNA or by inactivated SARS-CoV-2 virions. The analytes were spiked on filters and underwent an active or passive sampling; then, they were preserved at −80 °C for different numbers of days (0 to 54) before extraction and analysis. We found a mean recovery of 2.43%, except for the sample not preserved (0 days) that showed a recovery of 13.51%. We found a relationship between the number of days and the recovery percentage. The results presented show a possible issue that relates to the quartz matrix and SARS-CoV-2 RNA recovery. The results are in accordance with the already published studies that described similar methods for SARS-CoV-2 RNA field sampling and that reported non-detectable concentrations of RNA. These outcomes could be false negatives due to sample preservation conditions. Thus, until further investigation, we suggest, as possible alternatives, to keep the filters: (i) in a sealed container for preservation at 4 °C; and (ii) in a viral transport medium for preservation at a temperature below 0 °C.

Evaluation of N-acetylcysteine and glutathione as quenching agents for the analysis of halogenated disinfection by-products

Disinfection by-products (DBPs), formed from the reactions of disinfectants with natural organic matter and halides in drinking water, were considered to be cytotoxic and genotoxic, and might trigger various cancers. The relatively low concentration of DBPs in finished water (low µg/L or even ng/L levels) and the interference from water matrix inhibited in situ determination of DBPs. Moreover, the further formation and degradation of DBPs by disinfectants during the holding time (several hours to several days) from sample collection to analysis could adversely affect the determination of DBPs. To obtain accurate, precise and reliable data of DBP occurrence and formation, robust and reliable sample preservation is indispensable. However, the commonly used quenching agents (e.g., sodium sulfite, sodium thiosulfate, and ascorbic acid) for sample preservation can decompose reactive DBPs by reductive dehalogenation. This study evaluated the performance of N-acetylcysteine (NAC) and glutathione (GSH) as quenching agents for the analysis of halogenated DBPs by investigating the stoichiometry of the disinfectant-quenching agent reaction, the formation of DBPs during chlor(am)ination of NAC or GSH, and the effects of NAC or GSH on the stability of 18 individual DBPs and total organic halogen (TOX). Based on the results of this study, NAC and GSH were considered to be ideal quenching agents for the analysis of most DBPs and TOX, except halonitromethanes.

On-Site Viral Inactivation and RNA Preservation of Gargle and Saliva Samples Combined with Direct Analysis of SARS-CoV-2 RNA on Magnetic Beads.

Samples of nasopharyngeal swabs (NPS) are commonly used for the detection of SARS-CoV-2 and diagnosis of COVID-19. As an alternative, self-collection of saliva and gargle samples minimizes transmission to healthcare workers and relieves the pressure of resources and healthcare personnel during the pandemic. This study aimed to develop an enhanced method enabling simultaneous viral inactivation and RNA preservation during on-site self-collection of saliva and gargle samples. Our method involves the addition of saliva or gargle samples to a newly formulated viral inactivation and RNA preservation (VIP) buffer, concentration of the viral RNA on magnetic beads, and detection of SARS-CoV-2 using reverse transcription quantitative polymerase chain reaction directly from the magnetic beads. This method has a limit of detection of 25 RNA copies per 200 μL of gargle or saliva sample and 9–111 times higher sensitivity than the viral RNA preparation kit recommended by the United States Centers for Disease Control and Prevention. The integrated method was successfully used to analyze more than 200 gargle and saliva samples, including the detection of SARS-CoV-2 in 123 gargle and saliva samples collected daily from two NPS-confirmed positive SARS-CoV-2 patients throughout the course of their infection and recovery. The VIP buffer is stable at room temperature for at least 6 months. SARS-CoV-2 RNA (65 copies/200 μL sample) is stable in the VIP buffer at room temperature for at least 3 weeks. The on-site inactivation of SARS-CoV-2 and preservation of the viral RNA enables self-collection of samples, reduces risks associated with SARS-CoV-2 transmission, and maintains the stability of the target analyte.

Human Stool Preservation Impacts Taxonomic Profiles in 16S Metagenomics Studies.

Microbiotas play critical roles in human health, yet in most cases scientists lack standardized and reproducible methods from collection and preservation of samples, as well as the choice of omic analysis, up to the data processing. To date, stool sample preservation remains a source of technological bias in metagenomic sequencing, despite newly developed storage solutions. Here, we conducted a comparative study of 10 storage methods for human stool over a 14-day period of storage at fluctuating temperatures. We first compared the performance of each stabilizer with observed bacterial composition variation within the same specimen. Then, we identified the nature of the observed variations to determine which bacterial populations were more impacted by the stabilizer. We found that DNA stabilizers display various stabilizing efficacies and affect the recovered bacterial profiles thus highlighting that some solutions are more performant in preserving the true gut microbial community. Furthermore, our results showed that the bias associated with the stabilizers can be linked to the phenotypical traits of the bacterial populations present in the studied samples. Although newly developed storage solutions have improved our capacity to stabilize stool microbial content over time, they are nevertheless not devoid of biases hence requiring the implantation of standard operating procedures. Acknowledging the biases and limitations of the implemented method is key to better interpret and support true associated microbiome patterns that will then lead us towards personalized medicine, in which the microbiota profile could constitute a reliable tool for clinical practice.

The Diverse World of Protists-an Ideal Community with which to Introduce Microscopy in the Microbiology Teaching Laboratory.

ABSTRACTProtists and other eukaryotes are present in diverse terrestrial and aquatic environments. They can easily be collected from local ponds and streams. Although they are typically larger in size than prokaryotes, making them easy to study with even basic microscopes, microbiology laboratory courses often do not discuss them in detail and may only dedicate a short time to observing preserved samples. This laboratory exercise allows students to develop microscope skills, experience real world application of collecting and processing field samples, and delve deeper into the diverse world of protists and other microbial eukaryotes. Students may also engage by sharing their findings on the website iNaturalist to contribute to the scientific knowledge collected around the world. This laboratory module was initially designed for in-person learning but has been successfully adapted to remote learning and can also be applied to a complete online learning environment.

Comparison of pretreatment, preservation and determination methods for foliar pH of plant samples

Abstract To compare current methods of pretreatment/determination for plant foliar pH, we proposed a method for long-period sample preservation with little interference with the stability of foliar pH. Four hundred leaf samples from 20 species were collected and four methods of pH determination were used: refrigerated (stored at 4 °C for 4 days), frozen (stored at −16 °C for 4 days), oven-dried and fresh green-leaf pH (control). To explore the effects of different leaf:water mixing ratio on the pH determination results, we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10, and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15. The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods. Foliar pH of refrigerated and frozen green leaves did not significantly differ from that of fresh green-leaf, but drying always overrated fresh green-leaf pH. During the field sampling, cryopreservation with a portable refrigerator was an advisable choice to get a precise pH. For long-duration field sampling, freezing was the optimal choice, and refrigeration is the best choice for the short-time preservation. The different leaf:water mixing ratio significantly influenced the measured foliar pH. High dilution reduced the proton concentration and increased the measured pH. Our findings provide the conversion relationships between the existing pretreatment and measurement methods, and establish a connection among pH determined by different methods. Our study can facilitate foliar pH measurement, thus contributing to understanding of this interesting plant functional trait.

The Xiangya Ocular Tumor Bank: A Disease-Specific Biobank for Advancing Translational Research Into Ocular Tumors.

The pathogenesis and etiology of various ocular tumors remain largely unclear, limiting the development of diagnostic and treatment approaches for such tumors. Tissue samples from patients are also valuable resource to elucidate mechanisms underlying tumorigenesis. Here we present the early phase setup of an ocular tumor biobank at Xiangya Hospital. Blood and tissue samples along with associated clinical data were obtained from patients who underwent surgery in the Department of Ophthalmology of Xiangya Hospital from December 1, 2018 to January 31, 2020. Standardized operating protocols were developed for the collection, transportation, processing and preservation of ocular tumor samples. A total of 92 clinical cases suffered from 21 types of eye tumors and several undiagnosed eye diseases were covered. A total of 846 samples were preserved in the ocular tumor biobank, including 356 blood samples (42.1%), 324 plasma samples (38.3%), and 166 tissue samples (19.6%). Using the clinical data, we analyzed the prevalence of malignant ocular tumors in association with variables of age, gender, tumors' location and size, and presenting complaints of lump and proptosis. The factors predictive of malignant ocular tumors, included gender (B = 1.599; P = 0.025) and the symptom of proptosis (B = −2.534; P = 0.001). Overall, the setup of clinically-based ophthalmologic biobank could support pathological and translational research into ocular tumors.

Voices from the past: results of the ESP history of pathology working group survey on pathology museums

While keeping their original purpose of training medical students, pathology museums hold great biological value, offering unique specimens for scientific research through modern radiological, pathological and biomolecular techniques. Moreover, the artefacts, models and drawings displayed in these museums are a precious cultural and artistic heritage. Preservation of the anatomical samples and maintenance of the facilities are neither easy nor inexpensive and call for patronage. The development of a European Pathology Museum Network would undoubtedly facilitate study, access and divulgation of antique pathology collections. Data from a survey conducted by the European Society of Pathology (ESP) History of Pathology Working Group have allowed creation of a comprehensive, multifaceted portrait of European university museums, reflecting their history, diversity, geography, institutional status, stakeholders, projects, professionals, audiences, policies and best practices.

SAR Target Incremental Recognition Based on Hybrid Loss Function and Class-Bias Correction

The Synthetic Aperture Radar (SAR) target recognition model usually needs to be retrained with all the samples when there are new-coming samples of new targets. Incremental learning emerges to continuously obtain new knowledge from new data while preserving most previously learned knowledge, saving both time and storage. There are still three problems in the existing incremental learning methods: (1) the recognition performance of old target classes degrades significantly during the incremental process; (2) the target classes are easily confused when similar target classes increase; (3) the model is inclined to new target classes due to class imbalance. Regarding the three problems, firstly, the old sample preservation and knowledge distillation were introduced to preserve both old representative knowledge and knowledge structure. Secondly, a class separation loss function was designed to reduce the intra-class distance and increase the inter-class distance, effectively avoiding the confusion between old and new classes. Thirdly, a bias correction layer and a linear model was designed, which enabled the model to treat the old and new target classes more fairly and eliminate the bias. The experimental results on the MSTAR dataset verified the superior performance compared with the other incremental learning methods.

Investigation of miRNA expression profiles using cohort samples reveals potential early detectability of colorectal cancers by serum miR-26a-5p before clinical diagnosis.

Previous studies have investigated the usefulness of microRNA (miRNA/miR) expression data for the early detection of colorectal cancer (CRC). However, limited data are available regarding miRNAs that detect CRC before clinical diagnoses. Accordingly, the present study investigated the early detectability of CRC by miRNAs using the preserved serum samples of the cohort participants affected with CRC within 2 years of study enrollment. First, the significant miRNAs were revealed using clinical CRC samples for a (seven early CRCs and seven controls) microarray analysis based on significance analysis of microarrays. Next, replicability was verified by reverse transcription-quantitative (RT-q)PCR (eight early CRCs and eight controls, together with 12 CRCs and 12 controls). Finally, early detectability was tested using the cohort samples of Japan Multi-Institutional Collaborative Cohort Study (17 CRCs and 17 controls) to reveal how a certain number of patients developed CRC within 2 years after participation. In the discovery phase, miRNA expression measurements were conducted using a 3D-Gene Human miRNA Oligo Chip for 2,555 miRNAs, and RT-qPCR analyses were performed to validate the replicability. In the first validation set with eight CRCs with early clinical stage and eight age- and gender-matched controls, miR-26a-5p and miR-223-3p demonstrated the highest diagnostic accuracy of area under the curve (AUC)=1.000 (sensitivity and specificity 100%). In an examination of the predictability of CRC incidence using pre-clinical cohort samples, miR-26a-5p demonstrated good predictability of advanced CRC incidence with an AUC of 0.840. Overall, the present study revealed serum miR-26a-5p as a potential early detection marker for CRC.

Comparison between two cryopreservation techniques of human ovarian cortex: morphological aspects and the heat shock response (HSR).

This study was tailored to compare the cryopreservation of the human ovarian cortex using closed metal container vitrification or the slow-freezing technique. Superficial ovarian cortical tissue biopsies were collected from 12 participants who underwent gynaecological videolaparoscopy. The fragmented samples were allocated to three experimental conditions: (a) fresh ovarian tissue, (b) slow-freezing, and (c) vitrification with a metal closed container. After thawing or rewarming, cellular morphological analyses were performed to determine tissue viability. The cellular response to thermal stress was measured by a putative increase in the immune quantification of the heat shock protein 70kDa (heat shock protein 70kDa response - HSR) after a heat challenge (2h exposure at 42°C). Both the total number of intact follicles and the frequency of primordial follicles were higher in fresh ovarian tissue than in the preserved samples, regardless of the technique employed. There was a trend towards an increase in the absolute number of intact follicles in the tissue preserved by vitrification. After cryopreservation, a higher HSR was obtained after slow-freezing. These results indicate that both cryopreservation techniques present advantages and may be used as alternatives to ovarian tissue cryopreservation.

Establishing a Standardized Method for the Effective Intraoperative Collection and Biological Preservation of Brain Tumor Tissue Samples Using a Novel Tissue Preservation System: A Pilot Study

Glioblastoma (GB) is an aggressive tumor showing extensive intertumoral and intratumoral heterogeneity. Several possible reasons contribute to the historical inability to develop effective therapeutic strategies for treatment of GB. One such challenge is the inability to consistently procure high-quality biologically preserved specimens for use in molecular research and patient-derived xenograft model development. No scientifically derived standardized method exists for intraoperative tissue collection specifically designed with the fragility of RNA in mind. In this investigation, we set out to characterize matched specimens from 6 GB patients comparing the traditional handling and collection processes of intraoperative tissue used in most neurosurgical operating rooms versus an automated resection, collection, and biological preservation system (APS) which captures, preserves, and biologically maintains tissue in a prescribed and controlled microenvironment. Matched specimens were processed in parallel at various time points and temperatures, evaluating viability, RNA and protein concentrations, and isolation of GB cell lines. We found that APS-derived GB slices stored in an APS modified medium remained viable and maintained high-quality RNA and protein concentration for up to 24 hours. Our results showed that primary GB cell cultures derived in this manner had improved growth over widely used collection and preservation methods. By implementing an automated intraoperative system, we also eliminated inconsistencies in methodology of tissue collection, handling and biological preservation, establishing a repeatable and standardized practice that does not require additional staff or a laboratory technician to manage it.

Environmental DNA from Marine Waters and Substrates: Protocols for Sampling and eDNA Extraction.

Environmental DNA (eDNA) analysis has emerged in recent years as a powerful tool for the detection, monitoring, and characterization of aquatic metazoan communities, including vulnerable species. The rapid rate of adopting the eDNA approach across diverse habitats and taxonomic groups attests to its value for a wide array of investigative goals, from understanding natural or changing biodiversity to informing on conservation efforts at local and global scales. Regardless of research objectives, eDNA workflows commonly include the following essential steps: environmental sample acquisition, processing and preservation of samples, andeDNA extraction, followed by eDNA sequencing library preparation, high-capacity sequencing and sequence data analysis, or other methods of genetic detection. In this chapter, we supply instructional details for the early steps in the workflow to facilitate researchers considering adopting eDNA analysis to address questions in marine environments. Specifically, we detail sampling, preservation, extraction, and quantification protocols for eDNA originating from marine water, shallow substrates, and deeper sediments. eDNA is prone to degradation and loss, and to contamination through improper handling; these factors crucially influence the outcome and validity of an eDNA study. Thus, we also provide guidance on avoiding these pitfalls. Following extraction, purified eDNA is often sequenced on massively parallel sequencing platforms for comprehensive faunal diversity assessment using a metabarcoding or metagenomic approach, or for the detection and quantification of specific taxa by qPCR methods. These components of the workflow are project-specific and thus not included in this chapter. Instead, we briefly touch on the preparation of eDNA libraries and discuss comparisons between sequencing approaches to aid considerations in project design.

The application of Geostatistical software (SGeMS), Ilwis software and Kriging interpolation to simulate 3D stratigraphic structure model urban Rach Gia town, Kien Giang, Viet Nam

In recent decades, all of the previous researches for determination of the soil-rock characteristics implemented effectively such as geophysical method, static and dynamic penetration, chemical methods and blasting method and so on. These methods combined with experimental results in the laboratory. However, these methods lost much time, costs, and other environmental conditions that machines, tools, people, experimental environment, sample preservation, implemental methods, temperature, weather, and so on. From that, improvement of difficult problems that an urgent and essential method to build “3D spatial stratigraphic structure model in Rach Gia urban, Kien Giang in Viet Nam” was proposed and the results in the shorten time of design, construction time and the lowest costs that implemented by the Geostatistics (SGeMS), Ilwis software and Kriging interpolation. From the results of the 3D model of the stratigraphic structure shown fast for the soil characteristics (type of soils, states, colors, the thickness of soil layers, and mechanical properties) whereas it is not necessary to drill and measure in the laboratory and the field. Moreover, this method supplies scientists, Geology, and Civil engineer who can survey, design, and do construction easily and essentially. Especially, Geologists can predict in advance possible geology hazards during the construction time to ensure construction stability and save costs as low as possible.

Stabilization of swine faecal samples influences taxonomic and functional results in microbiome analyses

Studies on the microbiome of different species are on the rise, due to a growing interest in animal health and the safety of food products of animal origin. A challenge with studying animals’ microbiomes is to find methods that obtain a good representation of the microbial community of interest. Good unbiased sampling protocols are the basis for a solid experimental design, but may need to be done in environments where sample preservation could be difficult. In this study, we evaluate by shotgun sequencing the impact of stabilizing swine faeces samples using a commercial stabilizer (PERFORMAbiome • GUT | PB-200, DNA Genotek). Using stabilizer makes it possible to obtain DNA that is significantly less degraded than when the samples are not stabilized. Also, the results on the taxonomy and on the bacterial functions encoded in the microbiome are impacted by whether or not the samples are stabilized. Finally, the stabilization of samples that had already been frozen and stored at -80°C led to extraction and DNA quality results similar to those obtained from samples that were stabilized before freezing.

Morphological Identification of Edible Termites (Isoptera) in Luanda Sub-County, Kenya

Termites are social insects that live in colonies underground. Globally, there are 3000 termite species, of which 39% are found in Africa. Termites are used as food and livestock feed in most communities of the world. In Kenya, termites are consumed by many communities, especially in the western region. Termite species diversity across different parts of the Luanda sub-county was established as there are many edible and non-edible species in the area. This study assessed the species diversity of termites in Luanda sub-county, and characterized them morphologically. Termites were sampled in Luanda sub-county using the line transect method. The collected termites were preserved in tubes containing 70% Ethanol. The preserved samples were taken to the National Museums of Kenya for morphological identification up to species level. Species richness of each habitat was analyzed for diversity (Shannon-Wiener) index and Shannon index by using Vegan package version 1.16 - 32 in R. The differences in species composition and diversity of termites were analyzed using one-way ANOVA. Morphological identification recorded seven species, namely, Macrotermes herus, Macrotermes spp1, Macrotermes sp1, Pseudocanthotermes grandiceps, Macrotermes bellicosus, Macrotermes spp2 and Pseudocanthotermes militaris. The results of this study showed that the Shannon diversity index H was 0.3606 while Simpson index D was 0.20644, which implied a high species diversity of termites in Luanda sub-county a leading producer of edible termites in Kenya.

THE EFFECT OF LIPID-CAROTINOID CONCENTRATE FROM SHRIMP ON THE QUALITY AND PERIOD OF STORAGE OF PRESERVES

The raw material base of the fish industry of Ukraine is mainly represented by freshwater fish, which are characterized by a low content of polyunsaturated fatty acids of the ω3 family and do not meet the modern requirements of nutrition science for healthy nutrition. Therefore, the enrichment of food products from freshwater fish with these acids becomes relevant. The aim of work – to determine the effect of lipid-carotenoid concentrate from the Black Sea shrimp Palaemon adspersus Rathke, 1837 on the quality and period of storage preserves from carp Cyprinus carpio. The research was conducted in the laboratory of the meat, fish and seafood technology department of the faculty of food technology and product quality of agricultural products of National University of Life and Environmental Sciences of Ukraine in the autumn of 2022. Developed of the descriptors and an evaluation of the sensory characteristics of preserves from C. carpio with different concentrations of lipid-carotenoid concentrate (1, 2, 3 g/100 g of product) and control. The quality of preserves with supplements of lipid-carotenoid concentrate in the amount of 2 and 3 g/100 g of the product exceeded the control sample by intensity of smell, taste and consistency and overall impression. Determined a positive influence of lipid-carotenoid concentrate to a change in the safety indicators of lipids, which is manifested in the slowing down of the processes of primary oxidation according to the peroxide number and hydrolysis of lipids according to the acid number. In the control sample, the peroxide number after 2 months storage at a temperature of +4°C reached 4.23, in experimental – 2.33 mmol O2/kg of fat, which did not exceed the permissible values according to the requirements of the international standard. Accumulation of free fatty acids in preserved samples was more intensive. In the control sample, after 50 days of storage, the acid value is 5.67, which limits this indicator by the requirements of the standard – 4.5 mg KOH/g of fat, which allows reducing the storage period of the control sample to 40 days. The addition of lipid-carotenoid concentrate in the amount of 2 and 3 g/100 g of the product can extend the storage period to 60 days. Intake of preserved carp of 100 g with additives of lipid-carotenoid concentrate in the amount of 2.3 g/100 g of the product will ensure the daily rate of intake of ω3 fatty acids in accordance with the recommendations of the FAO (1 g per day for prevention). The research results approve the antioxidant properties of shrimp carotenoid concentrate and correlate with the previous publications in this direction. Prospects for further work will be related to the determination of indicators of the biological value of preserves from freshwater fish and additives of lipid-carotenoid concentrate and changes in microbiological indicators of preserves during storage.

ИЗУЧЕНИЕ КОНСЕРВИРУЮЩЕГО СВОЙСТВА МЕДА В СОСТАВЕ МАРИНАДОВ ДЛЯ МЯСА

The search for new potential «barriers» of microbiological spoilage and the possibility of combining them with other traditionally used methods of preserving the quality of meat is very important in connection with the development of new recipes for its marinating. The article describes the results of an experiment on the use of honey as a marinade as a chemical factor in the preservation of meat in combination with a physical method (cooling). According to the results obtained, honey in marinades in small quantities was not a preservative for meat samples, but, on the contrary, due to the high level of sugars, it becomes a «fodder base» for the development of microorganisms, without showing antibacterial properties. Therefore, one should take into account the fact that in a few hours the level of microflora can increase significantly and further insufficient culinary processing of the product can lead to poisoning of the end consumer.

Phytoplankton Composition and Abundance in Mbiakong River, Cross River Estuary, Niger Delta, Nigeria

The phytoplankton composition and abundance in Mbiakong River, Cross river estuary, Niger Delta, Nigeria was studied for a period of one year (March, 2021-February, 2022). Plankton net of mesh size 55µm was used to collect plankton samples from below the water surface, after towing for 5 minutes. The content was emptied into plastic containers and fixed immediately with 4% formalin in the field for preservation. After 48hrs in the laboratory, the preserved plankton samples were concentrated to 10 ml. The concentrated sample was agitated to homogenize before pipetting 1ml sub sample with sample pipette. Enumeration and identification were performed using a zeis inverted microscope at x400 and x 1000 magnification. Species identification was done using recommended keys and guides. A total of six hundred and fifteen (615) individual organisms comprising of thirty-five (35) species belonging to five (5) taxonomic groups were recorded from Mbiakong River. The most abundant group was the Bacillariophyceae which was represented by 12 species (302 organisms) consisting of 49.11%. This was followed by Chlorophyceae represented by 10 species (199 organisms) consisting of 32.36%, Cyanophyceae represented by 12 species (109 organisms) consisting of 17.72%, Euglenophyceae represented by 1 species (3 organisms) consisting of 0.33% and the least abundant was the Dinophyceae represented by 1 species (2 organisms) consisting of 0.14%. The study revealed that species composition and abundance was high in June.

Effect of garlic (Allium sativum) and Ginger (Zingiber officinale) on the microbial and sensorial quality of smoked mackerel fish (Scomber scombrus)

This study examined the effect of garlic (Allium sativum) and ginger (Zingiber officinale) on the microbial and sensorial quality of smoked mackerel fish (Scomber scombrus). Thirty six (36) pieces of fresh frozen Mackerel fish of 1.09kg average weight were purchased, dressed, dipped in a solution of 0% garlic or ginger (T0), 10% garlic (T1), 10% Ginger (T2) and 5% garlic and 5% ginger (T3) solution for 30 min, smoked dried and stored at 28±2 °C over the period of 60 days. Microbiological and sensory analyses were performed on the smoked fish samples. The result revealed that the garlic and ginger treatment of the smoked preserved fish sample were found very influential. The values of the total bacterial count and moulds and yeast count shows that there were significant variations (p≤ 0.05) among the samples. Samples treated with ginger and garlic had lower total bacterial count, yeast and mould count than the control. The organoleptic results showed that samples treated with garlic/ginger (T3) had the best acceptance than the other treatments.