As the Editor-in-Chief of <i>Microorganisms</i>, it is my pleasure to introduce a new Section of this journal [...]

IntroductionThere are concerns about microorganisms present on cannabis materials used in clinical settings by individuals whose health status is already compromised and are likely more susceptible to opportunistic infections from microbial populations present on the materials. Most concerning is administration by inhalation where cannabis plant material is heated in a vaporizer, aerosolized, and inhaled to receive the bioactive ingredients. Heating to high temperatures is known to kill microorganisms including bacteria and fungi; however, microbial death is dependent upon exposure time and temperature. It is unknown whether the heating of cannabis at temperatures and times designated by a commercial vaporizer utilized in clinical settings will significantly decrease the microbial loads in cannabis plant material.MethodsTo assess this question, bulk cannabis plant material supplied by National Institute on Drug Abuse (NIDA) was used to assess the impact of heating by a commercial vaporizer. Initial method development studies using a cannabis placebo spiked with Escherichia coli were performed to optimize culture and recovery parameters. Subsequent studies were carried out using the cannabis placebo, low delta-9 tetrahydrocannabinol (THC) potency and high THC potency cannabis materials exposed to either no heat or heating for 30 or 70 seconds at 190°C. Phosphate-buffered saline was added to the samples and the samples agitated to suspend the microorganism. Microbial growth after no heat or heating was evaluated by plating on growth media and determining the total aerobic microbial counts and total yeast and mold counts.Results and discussionOverall, while there were trends of reductions in microbial counts with heating, these reductions were not statistically significant, indicating that heating using standard vaporization parameters of 70 seconds at 190°C may not eliminate the existing microbial bioburden, including any opportunistic pathogens. When cultured organisms were identified by DNA sequence analyses, several fungal and bacterial taxa were detected in the different products that have been associated with opportunistic infections or allergic reactions including Enterobacteriaceae, Staphylococcus, Pseudomonas, and Aspergillus.

ABSTRACT: The possible contribution of brine-derived microflora to the sensory attributes of cheese is still a rather unexplored field. In this study, 365 bacteria and 105 yeast strains isolated from 11 cheese brines were qualitatively tested for proteolytic and lipolytic activities, and positive strains were identified by sequencing. Among bacteria, Staphylococcus equorum was the most frequent, followed by Macrococcus caseolyticus and Corynebacterium flavescens. As for yeasts, Debaryomyces hansenii, Clavispora lusitaniae, and Torulaspora delbrueckii were most frequently identified. A total of 38% of bacteria and 59% of yeasts showed at least 1 of the metabolic activities tested, with lipolytic activity being the most widespread (81% of bacteria and 95% of yeasts). Subsequently 15 strains of bacteria and 10 yeasts were inoculated in a curd-based medium and assessed via headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry to determine their volatilome. After a 30-d incubation at 12°C, most strains showed a viability increase of about 2 log cfu/mL, suggesting good adaptability to the cheese environment. A total of 26 compounds were detected in the headspace, carbonyl compounds and alcohols being the major contributors to the volatile profile of the curd-based medium. Multivariate analysis was carried out to elucidate the overall differences in volatiles produced by selected strains. Principal component analysis and hierarchical clustering analysis demonstrated that the brine-related microorganisms were separated into 3 different groups, suggesting their different abilities to produce volatile compounds. Some of the selected strains have been shown to have interesting aromatic potential and to possibly contribute to the sensory properties of cheese.

Genetically engineered microorganisms have applications in various domains, such as agriculture, bioscience, healthcare, life sciences, and research. The novel methods of the system Clustered Regularly Interspaced Short Palindromic Repeats associated with protein 9, which originates from archaeal and bacterial immune systems and allows significant improvements to modified strains of microorganisms, represented a major innovation in industrial biotechnology. The rapid advancement of genetically engineered microorganisms has shown potential for bioremediation, food enzyme production, probiotics, and pesticides. Recently, engineered microbes have been used in several industries, like dairy, pharmaceuticals, biotech, and agrochemicals. Modified microorganisms used as biosensors are improved with reporter genes that induce their expression depending on the nature and concentration of the compound of interest to monitor environmental pollution. Genetically engineered microorganisms have been considered a threat to the environment, animals, and human health. Insertion of a single gene into different cells can result in diverse outcomes, and the general pattern of gene expression can be changed. More advanced and better techniques should be developed and applied in the genetic engineering of microbes to minimize risks.

Nowadays, population growth, the global temperature increase, and the appearance of emerging diseases in important crops generate uncertainty regarding world food security. The use of agrochemicals has been the “go-to” solution for the control of phytopathogenic microorganisms, such as <i>Magnaporte oryzae</i>, causing blast disease in rice and other cereals; <i>Botrytis cinerea</i>, causing gray mold in over 500 plant species; and <i>Puccinia</i> spp., causing rust in cereals. However, their excessive use has harmed human health, as well as ecosystems (contaminating water, and contributing to soil degradation); besides, phytopathogens can develop resistance to them. The inoculation of plant growth-promoting microorganisms (PGPMs) to crops is a sustainable strategy for increasing the yield and quality of crops and mitigating biotic stresses. Likewise, PGPMs, such as <i>Pseudomonas</i>, <i>Bacillus</i>, and <i>Trichoderma</i>, can trigger a series of signals and reactions in the plant that lead to the induction of systemic resistance, a mechanism by which plants react to microorganism stimulation by activating their defense system, resulting in protection against future pathogen attack. These plant defense mechanisms help to mitigate biotic stresses that threaten global food security. Thus, the study of these mechanisms at molecular, transcriptomic, and metabolomic levels is indispensable to elucidate how stresses affect globally important crops.

Bivalve molluscan shellfish have been consumed for centuries. Being filter feeders, they may bioaccumulate some microorganisms present in coastal water, either naturally or through the discharge of human or animal sewage. Despite regulations set up to avoid microbiological contamination in shellfish, human outbreaks still occur. After providing an overview showing their implication in disease, this review aims to highlight the diversity of the bacteria or enteric viruses detected in shellfish species, including emerging pathogens. After a critical discussion of the available methods and their limitations, we address the interest of technological developments using genomics to anticipate the emergence of pathogens. In the coming years, further research needs to be performed and methods need to be developed in order to design the future of surveillance and to help risk assessment studies, with the ultimate objective of protecting consumers and enhancing the microbial safety of bivalve molluscan shellfish as a healthy food.

There is a constant need to maintain the quality of consumed food. In retrospect to the recent pandemic and other food-related problems, scientists have focused on the numbers of microorganisms that are present in different food items. As a result of changes in certain environmental factors such as temperature and humidity, there is a constant risk for the growth of harmful microorganisms, such as bacteria and fungi, in consumed food. This questions the edibility of the food items, and constant monitoring to avoid food poisoning-related diseases is required. Among the different nanomaterials used to develop sensors to detect microorganisms, graphene has been one of the primary materials due to its exceptional electromechanical properties. Graphene sensors are able to detect microorganisms in both a composite and non-composite manner, due to their excellent electrochemical characteristics such as their high aspect ratios, excellent charge transfer capacity and high electron mobility. The paper depicts the fabrication of some of these graphene-based sensors, and their utilization to detect bacteria, fungi and other microorganisms that are present in very small amounts in different food items. In addition to the classified manner of the graphene-based sensors, this paper also depicts some of the challenges that exist in current scenarios, and their possible remedies.

The main concerns of food spoilage in fruit juices are the off-flavours and off-odours caused by microorganisms. In order to ensure high quality products, these microorganisms must therefore be eliminated or below a certain limit. Trials using pear concentrate, a ready-to-drink pear drink and a carbonated pear drink, were performed in order to compare two detection methods for three different groups of microorganisms: Total Count, Yeast & Moulds and Alicyclobacillus spp. The two methods compared were the standardised IFU methods for these three groups as well as the currently used In House (IH) method for the Company at whose disposal this study was conducted. The objective of the study was to investigate if a switch from the IH method to the IFU method could be carried out by the Company. In order to do this, the results between the methods need to be comparable and of similar sensitivity. The obtained results showed a tendency for similarity between the IFU and IH method for Total Count as well as Yeasts & Moulds. Regarding Alicyclobacillus spp., it seemed that the sensitivity of the method was higher for IH than IFU. The difference was in part suspected to be due to the pre-incubation step included in IH, not found in IFU. It is recommended that a pre-incubation period is added to the IFU method as allowed by IFU and that more trials are performed. | Har du någonsin öppnat en flaska juice på morgonen för att sedan upptäcka att den luktar bacon? I så fall är det möjligt att en typ av bakterie som kallas Alicyclobacillus (förkortad ACB) har börjat växa i juicen. Inom juice-industrin är ACB - tillsammans med jäst, mögel och andra bakterier som kan växa i sura miljöer - en av de främsta bovarna som gör att produkter måste slängas eller återkallas. Det är därför viktigt för företag att ha en bra metod för att hitta dessa typer av mikroorganismer tidigt i produktionen. Detta är relevant både ur ett ekonomiskt och miljömässigt perspektiv för att minska matavfall. Eftersom miljön i juice oftast är väldigt sur så är det inga farliga mikroorganismer som kan leva där, men det finns mikroorganismer anpassade till sura miljöer som kan göra så att juicen smakar eller luktar äckligt. Detta arbete har jämfört två olika metoder för att hitta mikroorganismer i päronjuice för att se om metoderna kan jämföras med varandra. Den ena metoden är utvecklad av Företaget som arbetet utfördes på, medan den andra metoden är en standardiserad metod som används av många andra företag runt om i världen. Fördelen för Företaget att gå över till den standardiserade metoden är att de då lättare skulle kunna jämföra sina resultat med andra företag och producenter av exempelvis deras ingredienser. Resultaten visar att de båda metoderna är jämförbara om det växer jäst och mögel eller bakterier såsom Lactobacillus, vilka tolererar sura miljöer, i juicen. Växer det däremot ACB i juicen så är de lättare att hitta med Företagets egen metod än med den standardiserade. Innan Företaget kan välja att byta metod bör de därför göra fler undersökningar med ACB.

Abstract An increased frequency of droughts due to anthropogenic climate change can lead to considerable stress for soil microorganisms and their functioning within northern peatlands. A better understanding of the diversity and relative abundance of methane producing and oxidizing taxa, and their functional genes, can help predict the functional potential of peatlands and how the microorganisms respond to disturbances such as drought. To address knowledge gaps in the understanding of how functional genetic diversity shifts under drought conditions, we investigated a hemi boreal mire in Southern Sweden. Environmental parameters, including soil and air temperature, precipitation, and water table depth, as well as methane flux data were collected during the summer of 2017 under typical growing conditions, and in 2018 during a drought. In addition, the diversity and composition of genes encoding for methane metabolism were determined using the captured metagenomics technique. During drought we observed a substantial increase in air and soil temperature, reduced precipitation, and a lower water table depth. Taxonomic and functional gene composition significantly changed during the drought, while diversity indices, such as alpha and beta diversity, remained similar. These results indicate that methane producing and oxidizing microbial communities, and their functional genes, displayed a resilience to drought with specific genera having the ability to outcompete others under stress. Furthermore, our results show that although methane emissions are substantially reduced during drought, we can expect to see a shift toward more resilient methanogens and methanotrophs under future climate conditions.