Laboratory Media Research Articles

Production of Mycological Media using Local Raw Inedible Materials

The use of local inedible raw materials in the formulation of mycological laboratory medium which is cost effective was carried out using brewer’s spent grain (BSG) samples gotten from Intafact Breweries Onitsha, Anambra state. The BSG was mixed with 5g of cow blood, 20g of Ede mmuo (Caladium bicolor), 5g of Fiofio, and 20g of agar agar as a gelling agent. The other media was prepared with the same materials but without agar agar. The formulated media was inoculated with Aspergillus niger as the test fungus. The two different media were compared for gowth diameter. The fungal organism grew faster on agar agar medium with wider colony diameter. On agar-agar medium, the length on the first day for the four plates were 1cm each. Second day for the four plates include; plate 1(15.0mm), plate 2(20.0mm), plate 3(10mm), and plate 4(15mm). Third day include; plate 1(30mm), plate 2(40mm), plate 3(32mm), and plate 4(35mm). Fourth day include; plate 1(60mm), plate 2(50mm), plate 3(35mm), and plate 4(60mm). Non agar-agar medium, the length on the first day for the four plates were 3mm each. Second day for the four plates include; plate 1(10.0mm), plate 2(11.0mm), plate 3(11.0mm), and plate 4(10.0mm). Third day include; plate 1(12.0mm), plate 2(14.0mm), plate 3(13.0mm), and plate 4(13.0mm). Fourth day include; plate 1(15.0mm), plate 2(16.0mm), plate 3(14.0mm), and plate 4(15.0mm).

Assessment of marine antifouling property of fluoropolymer nanocomposite coating on steel substrate ‐ A preliminary assay in laboratory

AbstractThis paper presents the results of immersion assay on antifouling performance of a fluoropolymer nanocomposite coating on the steel substrate using natural seawater medium in laboratory. The fluoropolymer nanocomposite coating was composed in the presence of reinforcement additives, including organically modified titanium dioxide (m‐TiO2), organically modified zirconium dioxide nanoparticles (m‐ZrO2) and antifouling agent of Cu2O nanoparticles and fluoropolymer. The ratio of m‐TiO2/m‐ZrO2/Cu2O was fixed at 2/2/5 wt.% in comparison with the fluoropolymer weight. The immersion test was applied to evaluating the antifouling performance of the nanocomposite coating in the natural seawater and has been carried out in dynamic condition at the room temperature of 30 ± 0.1 oC during 60 days of testing. The change in characteristics of the nanocomposite coating was observed and recorded weekly including contact angle, color of coating and the released Cu ions content. Other characteristics such as infrared spectroscopy, surface morphology, abrasion resistance and adhesion of the nanocomposite coating were analyzed before and after testing. The obtained results showed that Cu ions could release with a low rate from the nanocomposite coating when rising immersion time and the release of Cu ions followed a linear equation. The contact angle and gloss of the coating were slightly reduced during testing period, indicating that the smoothness of the coating surface did not change significantly when immersed in natural seawater. The adhesion and abrasion resistance of the coating were almost unchanged after 60‐day testing. In summary, the nanocomposite coating has good antifouling performance when immersion under natural seawater in the laboratory, considering the above specific characteristics, including the synergistic effect of reinforcement fillers (m‐TiO2, m‐ZrO2 nanoparticles) and antifouling agent (Cu2O nanoparticles) in the polymer matrix. This in‐lab experiment in natural seawater medium has confirmed the nanocomposite coating's antifouling performance and facilitated practical deployment.

Physiology of Saccharomyces cerevisiae during growth on industrial sugar cane molasses can be reproduced in a tailor-made defined synthetic medium

Fully defined laboratory media have the advantage of allowing for reproducibility and comparability of results among different laboratories, as well as being suitable for the investigation of how different individual components affect microbial or process performance. We developed a fully defined medium that mimics sugarcane molasses, a frequently used medium in different industrial processes where yeast is cultivated. The medium, named 2SMol, builds upon a previously published semi-defined formulation and is conveniently prepared from some stock solutions: C-source, organic N, inorganic N, organic acids, trace elements, vitamins, Mg + K, and Ca. We validated the 2SMol recipe in a scaled-down sugarcane biorefinery model, comparing the physiology of Saccharomyces cerevisiae in different actual molasses-based media. We demonstrate the flexibility of the medium by investigating the effect of nitrogen availability on the ethanol yield during fermentation. Here we present in detail the development of a fully defined synthetic molasses medium and the physiology of yeast strains in this medium compared to industrial molasses. This tailor-made medium was able to satisfactorily reproduce the physiology of S. cerevisiae in industrial molasses. Thus, we hope the 2SMol formulation will be valuable to researchers both in academia and industry to obtain new insights and developments in industrial yeast biotechnology.

Physicochemical properties of Kakol (Suaeda aegyptiaca) essential oil nanoemulsion and its effect on the storage quality of rainbow trout (Oncorhynchus mykiss) during cold storage.

The study aims to analyze the chemical composition of Suaeda aegyptiaca essential oil (PSAE) by GC-MS, produce the nanoemulsified essential oil (NSAE) using ultrasound, and compare the antimicrobial and antioxidant activity of the PSAE and NSAE in laboratory medium and rainbow trout fish (Oncorhynchus mykiss). Geranyl-acetone (30.52%) and p-Vinylguaiacol (10.66%), and (e)-β-ionone (7.79%) were the main PSAE chemical compounds. The mean droplet size diameter, polydispersity index, and viscosity of NSAE were 179.67 nm, 0.255, and 0.96 cP, respectively. PSAE and NSAE showed a moderate antiradical potential against DPPH- and ABTS-free radicals (50 < IC50 < 250 μg mL-1). There was no significant difference between antiradical scavenging of PSAE and NSAE (p > .05). E. faecalis and K. pneumonia were the most and lowest sensitive bacteria to PSAE and NSAE, respectively. Examining different treatments on the shelf-life of minced fish showed that Kakol essential oil could improve the shelf-life of fish between 12.5% and 60% (depending on quality index). There was no significant difference between the bioactivity of PSAE and NSAE, which means that the nanoemulsion showed acceptable performance at lower essential oil concentrations.

Development of Android-Based Chemistry Virtual Laboratory Media on Acid-Base Materials for 11th Grade High School Students

Development of Android-Based Chemistry Virtual Laboratory Media on Acid-Base Materials for 11th Grade High School Students

Development of UV-VIS Spectrophotometer Virtual Laboratory Media for Instrumental Analytical Chemistry Digital Practicum

&lt;p&gt;&lt;span data-preserver-spaces="true"&gt;The demands of 21st Century learning are now in the Industrial Revolution Era 4.0 with 4C learning characters. Educators must develop their creativity to improve the quality of learning so that students can be more creative in learning. &lt;/span&gt;&lt;em&gt;Instrumental Analytical Chemistry&lt;/em&gt;&lt;span data-preserver-spaces="true"&gt; is a course that studies modern instrumentation for chemical analysis. The instrumentation is unavailable in the laboratory because it is costly. This research aims to develop a virtual laboratory media UV-Vis Spectrophotometer that can be used in the digital practicum of the Instrumental Analytical Chemistry Course. The method used is development research (R &amp;amp; D) by adapting the multimedia model ID Hannafin &amp;amp; Peck, using Macromedia flash applications. This research shows that the UV-Vis Spectrophotometer virtual lab developed provides excellent feasibility results and is also effective for use in lectures and digital practicum of Instrumental Analytical Chemistry lectures. &lt;/span&gt;&lt;/p&gt;

Virtual Laboratory Design for Learning Electro-Pneumatic Practices in Vocational High Schools

&lt;p style="text-align:justify"&gt;Teaching a subject in a vocational high school (VHS) requires specialized instructional design strategies. Recently, instructional VHS used a computer-based platform to teach theory and practice. The computer will assist teachers in creating instructional media. This study aims to design augmented reality-based virtual laboratory media for electro-pneumatic practicum learning in order to ease teachers and students to learn the pneumatic practice. It is specially designed for practical learning purposes. The method used in this research is research and development. The assessment results from Instructional design experts 4.5, material experts 4.5, media experts 4.4, and language experts 4.8. Based on the assessment of experts, this augmented reality-based virtual laboratory media is feasible to use. Next, the results of this study are a prototype of students' pneumatic practice tools installed on mobile phones consisting of eight worksheets. In the designed augmented reality media, 1) 3-dimensional pneumatics can be rotated in all directions so that students understand. 2) Pneumatic job sheet, where on the augmented reality media designed for the simulation circuit, there is an explanation of the components and how they work, and a simulation through markers.&lt;/p&gt;

Development of Virtual Laboratory Media for Virus Materials to Improve Students' Higher Order Thinking Skills in Senior High School

This study aims to (1) describe the validity of under-development virtual laboratory media of virus material, (2) describe practicality of under-development virtual laboratory media of virus material, (3) describe effectiveness of under-development virtual laboratory media of virus material.This study is research and development using the ADDIE model (analyze, design, develop, implement, and evaluate). The study instruments are compiled including virtual laboratory media validation sheets for experts, virtual laboratory media practicality sheets for biology teachers and student, critical thinking questions and procedural skills. The application of virtual laboratory media includes limited trials and field trials. The field trial subjects are students of class X at State Senior High School 1 Wonosobo. The field trial design for this research is a pretest-posttest control group design. The practicality of virtual laboratory media is analyzed from data on filling out the eligibility sheet by media and material experts by managing the average score and categorizing the data into ideal ratings. The practicality of virtual laboratory media is analyzed from the data of filling in the practicality sheet by the biology teacher by managing the average score by categorizing the data as an ideal assessment. The effectiveness of virtual laboratory media is analyzed from n-gain data on critical thinking and procedural skills using the Mann-Whitney U test.The results showed that (1) the under-development virtual laboratory media is valid for use in teaching biology on viruses based on expert validation (2) the under-development virtual laboratory media is practically used in learning biology material on viruses based on the biology teacher's assessment. Thus, it becomes a solution for laboratory tools and materials for State Senior High School 1 Wonosobo which can facilitate their students in improving HOTS skill (3) the under-development virtual laboratory media effectively improves students' higher-order thinking skills based on Mann Withey U analysis on trial data.

Compensatory mutations reducing the fitness cost of plasmid carriage occur in plant rhizosphere communities.

Plasmids drive bacterial evolutionary innovation by transferring ecologically important functions between lineages, but acquiring a plasmid often comes at a fitness cost to the host cell. Compensatory mutations, which ameliorate the cost of plasmid carriage, promote plasmid maintenance in simplified laboratory media across diverse plasmid-host associations. Whether such compensatory evolution can occur in more complex communities inhabiting natural environmental niches where evolutionary paths may be more constrained is, however, unclear. Here we show a substantial fitness cost of carrying the large conjugative plasmid pQBR103 in Pseudomonas fluorescens SBW25 in the plant rhizosphere. This plasmid fitness cost could be ameliorated by compensatory mutations affecting the chromosomal global regulatory system gacA/gacS, which arose rapidly in plant rhizosphere communities and were exclusive to plasmid carriers. These findings expand our understanding of the importance of compensatory evolution in plasmid dynamics beyond simplified lab media. Compensatory mutations contribute to plasmid survival in bacterial populations living within complex microbial communities in their environmental niche.

First report of enterotoxigenic Staphylococcus argenteus as a foodborne pathogen

Staphylococcal enterotoxins preformed in food are the causative agents of staphylococcal food poisoning outbreaks (SFPO). In this study we characterised in depth two coagulase-positive non-pigmented staphylococci involved in two independent outbreaks that occurred in France. While indistinguishable from Staphylococcus aureus using PCR methods and growth phenotype comparisons, both isolates were identified as Staphylococcus argenteus by whole genome sequencing. The genomes were analysed for the presence of enterotoxin genes, whose expression was determined in laboratory medium and, for the first time, in artificially-contaminated milk samples by using liquid chromatography-mass spectrometry and ELISA methods. The concentration measured for the SEB toxin in milk (0.67 ng/ml) was comparable to concentrations reported for other types of enterotoxins behind SFPO. From a collection of publicly available genomes, we performed an unprecedented systematic investigation of the enterotoxin gene set of S. argenteus, including variants and pseudogenes. The most prevalent genes were sex, followed by sel26, sel27 and sey. The egc cluster was less frequent and most of the time carried a dysfunctional seg gene. Our results shed light on the enterotoxigenic properties of S. argenteus, and emphasize the importance in monitoring of S. argenteus as an emerging foodborne pathogen.

Development of Biology Learning Media Assisted by Construct2 to Improve Critical Thinking Skills

The construct2 software is an HTML5 based Game Builder Tool. Construct2 can be used in the development of biology learning media assisted by construct2 or HTML5 to improve critical thinking skills. This type of research is research and development (Research and Development) which is accommodated from Sugiyono (2008) which was developed according to the conditions and situations. The research data instruments consist of assessment instruments by validators (material, language, and media), and media-based questionnaires based on teacher and student responses. The research data is in the form of media data validation from a team of experts, the results of the virtual laboratory media feasibility test, and the results of the learning media effectiveness test. The research population consisted of 5 SMA 1 BELO classes consisting of IPA 1, IPA 2, IPA 3, IPA 4 with a total of 130 students. The research subjects consisted of 67 students from Senior High School Negeri 1 Belo, West Nusa Tenggara, Indonesia. The result of the research is an application-based virtual laboratory application that can be programmed using Construct2 or HTML5 software. The results of the validity test according to experts ranged from 97%, while the exact location was 87%. The implications of this research are expected to be able to contribute to researchers, practitioners, to be able to optimize construction in making 3-dimensional virtual laboratory media

PENGARUH PENGGUNAAN PHYPHOX BERBASIS INKUIRI TERBIMBING TERHADAP HASIL BELAJAR FISIKA MAHASISWA

The Physics learning process in this digital era still has many obstacles including limited laboratory equipment and media to facilitate physics learning. During the Covid-19 pandemic, using Phyphox as a physics learning media on Simple Harmonic Motion material is still lacking. This study aims to determine the effect of using the Phyphox application based on guided inquiry on student physics learning outcomes on simple pendulum material. This research is experimental research with one group pretest &amp; posttest design. The population is physics students of Universitas Negeri Manado, and the sample is the Class of 2020. Analysis of the data obtained shows that there is an influence on the use of guided inquiry-based Phyphox on physics learning outcomes in physics student’s class of 2020. Based on the results of the average pre-test and post-test data, which increased from 59.33 -82.00. The t-test results obtained the value of tcount = 7.982 and tTabel = 1.761 with a significant level of 5%. therefore tcount &lt; tTabel (-7.982 &lt; 1.761) then: H0 is accepted and H1 is rejected. So, it can be concluded that with the application of the use of Phyphox applications can further improve student physics learning outcomes.

Comparative proteome analysis of different Saccharomyces cerevisiae strains during growth on sucrose and glucose

Both the identity and the amount of a carbon source present in laboratory or industrial cultivation media have major impacts on the growth and physiology of a microbial species. In the case of the yeast Saccharomyces cerevisiae, sucrose is arguably the most important sugar used in industrial biotechnology, whereas glucose is the most common carbon and energy source used in research, with many well-known and described regulatory effects, e.g. glucose repression. Here we compared the label-free proteomes of exponentially growing S. cerevisiae cells in a defined medium containing either sucrose or glucose as the sole carbon source. For this purpose, bioreactor cultivations were employed, and three different strains were investigated, namely: CEN.PK113-7D (a common laboratory strain), UFMG-CM-Y259 (a wild isolate), and JP1 (an industrial bioethanol strain). These strains present different physiologies during growth on sucrose; some of them reach higher specific growth rates on this carbon source, when compared to growth on glucose, whereas others display the opposite behavior. It was not possible to identify proteins that commonly presented either higher or lower levels during growth on sucrose, when compared to growth on glucose, considering the three strains investigated here, except for one protein, named Mnp1—a mitochondrial ribosomal protein of the large subunit, which had higher levels on sucrose than on glucose, for all three strains. Interestingly, following a Gene Ontology overrepresentation and KEGG pathway enrichment analyses, an inverse pattern of enriched biological functions and pathways was observed for the strains CEN.PK113-7D and UFMG-CM-Y259, which is in line with the fact that whereas the CEN.PK113-7D strain grows faster on glucose than on sucrose, the opposite is observed for the UFMG-CM-Y259 strain.

DESAIN LABORATORIUM VIRTUAL BERBASIS IJEN GEOPARK PADA MATERI IPA DI SMP SEBAGAI MEDIA PEMBELAJARAN INTERAKTIF

The virtual laboratory is an IT-based learning media. The purpose of this study was to develop a virtual laboratory design to increasing conceptual understanding of science material at the junior high school level on science material with topics of physics, chemistry, biology, and earth sciences. This virtual laboratory was developed as a form of utilizing technology in the field of education, where the development of information technology is currently very supportive of implementing practical simulations in a virtual laboratory. The research method of this research applies the Research and Development (R&amp;D) method with 3D steps. The development steps include: identification, design, and development. Validation stage of media experts, material experts and media users to assess the feasibility of the media and test development to see the effectiveness of using media in learning as well as student responses to the effectiveness of learning by using virtual laboratory media.

Integrating pH into the metabolic theory of ecology to predict bacterial diversity in soil.

Microorganisms play essential roles in soil ecosystem functioning and maintenance, but methods are currently lacking for quantitative assessments of the mechanisms underlying microbial diversity patterns observed across disparate systems and scales. Here we established a quantitative model to incorporate pH into metabolic theory to capture and explain some of the unexplained variation in the relationship between temperature and soil bacterial diversity. We then tested and validated our newly developed models across multiple scales of ecological organization. At the species level, we modeled the diversification rate of the model bacterium Pseudomonas fluorescens evolving under laboratory media gradients varying in temperature and pH. At the community level, we modeled patterns of bacterial communities in paddy soils across a continental scale, which included natural gradients of pH and temperature. Last, we further extended our model at a global scale by integrating a meta-analysis comprising 870 soils collected worldwide from a wide range of ecosystems. Our results were robust in consistently predicting the distributional patterns of bacterial diversity across soil temperature and pH gradients-with model variation explaining from 7 to 66% of the variation in bacterial diversity, depending on the scale and system complexity. Together, our study represents a nexus point for the integration of soil bacterial diversity and quantitative models with the potential to be used at distinct spatiotemporal scales. By mechanistically representing pH into metabolic theory, our study enhances our capacity to explain and predict the patterns of bacterial diversity and functioning under current or future climate change scenarios.

Oxidative stress in Arthrospira platensis by two organophosphate pesticides.

Although it is known that organophosphate insecticides are harmfull to aquatic ecosystems, oxidative damages caused by Dimethoate and Chlorpyrifos are not studied on Arthrospira platensis Gomont. In this study, various Chlorpyrifos (0-150 µg mL-1) and Dimethoate (0-250 µg mL-1) concentrations were added to the culture medium in laboratory to evaulate growth rate, chlorophyll-a content and antioxidant parameters of A. platensis. Optical Density (OD560) and chlorophyll-a decreased compared to the control for seven days in both pesticide applications. Superoxide dismutase (SOD) activity increased at 50 µg mL-1 Chlorpyrifos concentration but it decreased at all concentrations. Although Ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased with Chlorpyrifos application, they did not change with Dimethoate application. Malondialdehyde (MDA) amount decreased at 150 µg mL-1 Chlorpyrifos concentration but it increased in Dimethoate application. The H2O2 content were increased in both applications. Proline decreased in 50 and 75 µg mL-1 Chlorpyrifos concentrations and increased at 150 µg mL-1 concentration, while it increased at 25 µg mL-1 Dimethoate concentration. The results were tested at 0.05 significance level. These pesticides inhibit A. platensis growth and chlorophyll-a production and cause oxidative stress. The excessive use may affect the phytoplankton and have negative consequences in the aquatic ecosystem.

Bacteriological and Immunological study of kidney failure patients infected with urinary tract infections

Urinary tract infections (UTIs) are one of the most common medical conditions in women and men. They are caused by bacteria that enter the urinary tract through the urethra or the skin around the genitals. In this study, 102 urine samples were collected from 74 patients infected UTIs and 28 patients infected with urinary tract infections with kidney failure (UTIs-KF) admitted to a general hospital in AL-Najaf City, Iraq, between October to 2022 and March 2023 and 30 healthy individuals as control group. Standard laboratory methods were used to culture urine and to diagnose all bacterial isolates that were grown on laboratory media. The levels of cytokines IL-6 and IL-33 were detected by ELISA technique in the serum of control and patients. The results proved that age group 41-50 years old was the most UTIs infected with 31 patients (30.3%) followed by the age group ≤51 with 25 patients (24.5%). Out of total of 102 urine samples, there were 106 bacterial isolates, E.coli was the most dominate bacteria with 50 isolates (47%) followed by K.pneumoniae 18 isolates (17%), P.mirabilis 13 (12.7%), S.saprophyticus 10(9.5%), S.aureus 9(8.5%) and E.faecalis 6(6%). IL-6 and IL-33 were significantly higher in the UTIs and UTIs-KF patients, compared with the control group.

Augmented reality for studying hands on the human body for elementary school students

Augmented Reality (AR) media has become a utilization or an intermediary tool in everyday life. Augmented Reality has become a medium to contribute to human life, such as games, virtual tourism objects, and learning media. However, the application of Augmented Reality media in the world of education as a learning medium is still rarely used. Therefore, the holding of this research is as a form of contribution to the development of Augmented Reality media as a learning medium. The form of contribution from this research is a simple Augmented Reality created by using qualitative method to collect and analyze the elementary students data and Marker Based Tracking method resulting an application that has a function as a hand-shaped prop teaching aid for learning the body parts of the hands in elementary school students. With this learning media, it is hoped that it would help teachers and elementary school students in studying the parts of human body. All elementary school teachers can use the Aplikasi AR Belajar Bagian Tangan as a teaching medium in elementary school laboratories on their elementary school students or as a prop while students listening to their teacher explanations while seeing which parts of the hand are pointed out by elementary school teachers through the Aplikasi AR Belajar Bagian Tangan. This Aplikasi AR Belajar Bagian Tangan may provide elementary school students with their study and experience in using AR as a learning medium that can improve students’ analytical skills.

Multiple stressor effects on a model soil nematode, Caenorhabditis elegans: Combined effects of the pathogen Klebsiella pneumoniae and zinc oxide nanoparticles

Research utilizing the model soil nematode Caenorhabditis elegans has revealed that agriculturally relevant nanoparticles (NP), such as zinc oxide NP (ZnONP), cause toxicity at low concentrations and disrupt molecular pathways of pathogen resistance. However, in most nanotoxicity assessments, model organisms are exposed to a single stressor but in nature organisms are affected by multiple sources of stress, including infections, which might exacerbate or mitigate negative effects of NP exposure. Thus, to expand our understanding of the environmental consequences of released NP, this project examined the synergistic/antagonistic effects of ZnONP on C. elegans infected with a common pathogen, Klebsiella pneumoniae. Individual exposures of C. elegans to ZnONP, zinc sulfate (Zn2+ ions) or K. pneumoniae significantly decreased nematode reproduction compared to controls. To assess the combined stress of ZnONP and K. pneumoniae, C. elegans were exposed to equitoxic EC30 concentrations of ZnONP (or Zn ions) and K. pneumoniae. After the combined exposure there was no decrease in reproduction. This complete elimination of reproductive toxicity was unexpected because exposures were conducted at EC30 Zn concentrations and reproductive toxicity due to Zn should have occurred. Amelioration of the pathogen effects by Zn are partially explained by the Zn impact on the K. pneumoniae biofilm. Quantitative assessments showed that external biofilm production and estimated colony forming units (CFU) of K. pneumoniae within the nematodes were significantly decreased. Taken together, our results suggest that during the combined exposure of C. elegans to both stressors Zn in ionic or particulate form inhibits K. pneumoniae ability to colonize nematode's intestine through decreasing pathogen biofilm formation. This highlights the unpredictable nature of combined stressor effects, calling into question the utility of exposures in simplified laboratory media.

Variability in Cold Tolerance of Food and Clinical Listeria monocytogenes Isolates.

The aim of this study was to investigate the level of strain variability amongst food and clinical Listeria monocytogenes isolates growing at low temperatures (4 and 7 °C) in both laboratory media and real food matrices. Isolates (n = 150) grown in laboratory media demonstrated a large variation in growth profiles measured using optical density. Overall, it was noted that clinical isolates exhibited a significantly higher growth rate (p ≤ 0.05) at 7 °C than the other isolates. Analysis of variance (ANOVA) tests of isolates grouped using Multi Locus Sequence Typing (MLST) revealed that clonal complex 18 (CC18) isolates were significantly (p ≤ 0.05) faster growing at 4 °C than other CC-type isolates while CC101, CC18, CC8, CC37 and CC14 were faster growing than other CC types at 7 °C. Euclidean distance and Ward method-based hierarchical clustering of mean growth rates classified 33.33% of isolates as faster growing. Fast and slow growing representative isolates were selected from the cluster analysis and growth rates were determined using plate count data in laboratory media and model food matrices. In agreement with the optical density experiments, CC18 isolates were faster and CC121 isolates were slower than other CC types in laboratory media, UHT milk and fish pie. The same trend was observed in chocolate milk but the differences were not statistically significant. Moreover, pan-genome analysis (Scoary) of isolate genome sequences only identified six genes of unknown function associated with increased cold tolerance while failing to identify any known cold tolerance genes. Overall, an association that was consistent in laboratory media and real food matrices was demonstrated between isolate CC type and increased cold tolerance.