Advances in signal amplification strategies applied in pathogenic bacteria apta-sensing analysis-A review.

Pathogenic bacteria are primarily kinds of food hazards that provoke serious harm to human health via contaminated or spoiled food. Given that pathogenic bacteria continue to reproduce and expand once they contaminate food, pathogenic bacteria of high concentration triggers more serious losses and detriments. Hence, it is essential to detect low-dose pollution at an early stage with high sensitivity. Aptamers, also known as "chemical antibodies", are oligonucleotide sequences that have attracted much attention owing to their merits of non-toxicity, small size, variable structure as well as easy modification of functional group. Aptamer-based bioanalysis has occupied a critical position in the field of rapid detection of pathogenic bacteria. This is attributed to the unique advantage of using aptamers as recognition elements in signal amplification strategies. The signal amplification strategy is an effective means to improve the detection sensitivity. Some diverse signal amplification strategies emphasize the synthesis and assembly of nanomaterials with signal amplification capabilities, while others introduce various nucleic acid amplification techniques into the detection system. This review focuses on a variety of signal amplification strategies employed in aptamer-based detection approaches to pathogenic bacteria. Meanwhile, we provided a detailed introduction to the design principles and characteristics of signal amplification strategies, as well as the improvement of sensor sensitivity. Ultimately, the existing issues and development trends of applying signal amplification strategies in apta-sensing analysis of pathogenic bacteria are critically proposed and prospected. Overall, this review discusses from a new perspective and is expected to contribute to the further development of this field.

Plant-based foods as meat and fat substitutes.

Animal proteins have in the past been used in food production due to their functional properties that range from gelation and emulsification to foaming ability and stability. However, animal husbandry has been shown to be a major contributor to global warming and climate change. Consequently, there has been a drive toward the use of alternative proteins, for example, proteins from plant sources which are perceived to be cheaper, healthier, and sustainable. The use of trans and saturated fatty acids in the food industry has been associated with various health issues that include an increased risk of metabolic disorders. This has resulted in an increased search for fat substitutes that are healthier and sustainable. To contribute toward a reduction in the consumption of meats from animal sources and the consumption of trans and saturated fatty acids, the formulation of plant-based meat and fat analogs/substitutes has been carried out. However, there has been a lower acceptance of these meat or fat substitutes which was attributed to their sensorial and textural properties that fail to mimic or resemble real fat or meat. Therefore, this review aims to discuss the advances that have been made when it comes to plant-based meat and fat substitutes. Additionally, consumer perception and acceptance of these products will be reviewed as well as future markets will be discussed and the opportunities and challenges that exist in the formulation of these products will be explored.

Label-free colorimetric apta-assay for detection of Escherichia coli based on gold nanoparticles with peroxidase-like amplification.

In this work, aptamers against E. coli with better performance were obtained via cell systematic evolution of ligands by exponential enrichment (cell-SELEX) and dissociation constants (Kd) of aptamers were estimated to range from 133.87 to 199.44 nM. Furthermore, the selected aptamer was employed for label-free colorimetric detection of E. coli using gold nanoparticles (AuNPs) with peroxidase-like activity to catalyze the oxidation of tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to produce color development. This colorimetric apta-assay started with an aptamer-bacteria binding step, and the concentration of residual aptamers after binding depended on the amount of target bacteria. Then, the amount of separated residual aptamers determined the degree of cetyltrimethylammonium bromide (CTAB)-inhibited catalytic activity of AuNPs, which resulted in a color change from dark blue to light blue. Owing to the excellent peroxidase activity of AuNPs, they could emit strong visible color intensity in less than 1 minute to improve visual detection sensitivity. Under optimized conditions, the sensitivity of detection was 5 × 103 CFU mL-1 visually and 75 CFU mL-1 using the UV-vis spectrum with a linear range from 5 × 102 to 1 × 106 CFU mL-1. And it had shown a good recovery rate in real samples of water, juice and milk compared with classical counting methods.

Beer Safety: New Challenges and Future Trends within Craft and Large-Scale Production.

The presence of physical, chemical, or microbiological contaminants in beer represents a broad and worthy problem with potential implications for human health. The expansion of beer types makes it more and more appreciated for the sensorial properties and health benefits of fermentation and functional ingredients, leading to significant consumed quantities. Contaminant sources are the raw materials, risks that may occur in the production processes (poor sanitation, incorrect pasteurisation), the factory environment (air pollution), or inadequate (ethanol) consumption. We evaluated the presence of these contaminants in different beer types. This review covers publications that discuss the presence of bacteria (Lactobacillus, Pediococcus), yeasts (Saccharomyces, Candida), moulds (Fusarium, Aspergillus), mycotoxins, heavy metals, biogenic amines, and micro- and nano-plastic in beer products, ending with a discussion regarding the identified gaps in current risk reduction or elimination strategies.

Is cultured meat a promising consumer alternative? Exploring key factors determining consumer's willingness to try, buy and pay a premium for cultured meat.

Cultured meat is a relatively new product, enjoying consumer appreciation as a more sustainable meat option. The present study builds on a sample from a diverse set of countries and continents, including China, the US, the UK, France, Spain, Netherlands, New Zealand, Brazil, and the Dominican Republic and uses partial least square structural equation modelling. The proposed conceptual model identified key factors driving and inhibiting consumer willingness to try, buy, and pay a price premium for cultured meat. Results relate to the overall sample of 3091 respondents and two sub-sample comparisons based on gender and meat consumption behaviour. Food neophobia, having food allergies, being a locavore, and having concerns about food technology were found to be inhibiting factors towards willingness to try, buy, and pay a price premium for cultured meat. Food curiosity, meat importance, and a consumer's perception of cultured meat as a realistic alternative to regular meat were found to be important drivers that positively impacted consumers' willingness to try, buy and pay more. Best practice recommendations address issues facing marketing managers in food retail and gastronomy.

Understanding Key Factors Influencing Consumers' Willingness to Try, Buy, and Pay a Price Premium for Mycoproteins.

Mycoprotein is a fungal-based meat alternative sold in food retail in various countries around the world. The present study builds on a multi-national sample and uses partial least square structural equation modeling. The proposed conceptual model identified key factors that are driving and inhibiting consumer willingness to try, buy, and pay a price premium for mycoprotein. The results relate to the overall sample of 4088 respondents and to two subsample comparisons based on gender and meat consumption behavior. The results show that the biggest drivers of willingness to consume mycoprotein were healthiness, followed by nutritional benefits, safe to eat, and sustainability. Affordability and taste had mixed results. Willingness to consume mycoprotein was inhibited if nutritional importance was placed on meat and, to a lesser extent, if the taste, texture, and smell of meat were deemed important. Best practice recommendations address issues facing marketing managers in the food industry.

Identifying Consumer Groups and Their Characteristics Based on Their Willingness to Engage with Cultured Meat: A Comparison of Four European Countries.

Cultured meat, as a product of recent advancement in food technology, might become a viable alternative source of protein to traditional meat. As such, cultured meat production is disruptive as it has the potential to change the demand for traditional meats. Moreover, it has been claimed it can be more sustainable regarding the environment and that it is, perhaps, a solution to animal welfare issues. This study aimed at investigating associations between the consumer groups and demographic and psychographic factors as well as identifying distinct consumer groups based on their current willingness to engage with cultured meat. Four European countries were studied: the Netherlands (NL), the United Kingdom (UK), France (FR) and Spain (ES). A sample of 1291 responses from all four countries was collected between February 2017 and March 2019. Cluster analysis was used, resulting in three groups in the NL and UK, and two groups in FR and ES. The results suggest that Dutch consumers are the most willing to engage with cultured meat. Food neophobia and food technology neophobia seem to distinguish the groups the clearest. Moreover, there is some evidence that food cultural differences among the four countries seem to be also influencing consumers' decision.

Drivers and Inhibitors in the Acceptance of Meat Alternatives: The Case of Plant and Insect-Based Proteins.

Insects as an alternative protein source has gained traction for its advantageous environmental impact. Despite being part of many traditional food cultures, insects remain a novelty in Western cultures and a challenging concept for many. Even though plant-based protein alternatives are not facing the same barriers, product unfamiliarity and limited exposure hinder adoption, which could be detrimental to growth within the food sector. This study is aimed at evaluating plant- and insect-based proteins as alternative dietary proteins. A model indicating the drivers of consumer attitudes towards meat-alternative proteins and consumer willingness to try, buy, and pay a premium was tested. Further, 3091 responses were collected using surveys in nine countries: China, USA, France, UK, New Zealand, Netherlands, Brazil, Spain, and the Dominican Republic. Structural Equation Modelling was used to analyze the data. We found that consumer's behavioral intentions towards both plant-based and insect-based alternatives are inhibited by food neophobia but to an extent, are amplified by the perceived suitability and benefits of the protein, which in turn are driven by nutritional importance, environmental impact, healthiness, and sensory attributes for both alternatives. The expectation of the nutritional value of meat is the strongest (negative) influence on perceived suitability/benefits of plant-based protein and willingness to try, buy, and pay more for plant-based proteins, but it only has a relatively small impact on the suitability/benefits of insect-based protein and no impact on willingness to try, buy, and pay more for insect-based proteins. Overall, we conclude that consumer adoption towards meat alternatives is complex and is strengthened by the perceived suitability/benefits of the protein and general importance of perceived food healthiness and sustainability. Conversely, adoption is hindered by dietary factors and the experiential importance of meat and food neophobia.

Calcium phosphate coated core-shell protein nanocarriers: Robust stability, controlled release and enhanced anticancer activity for curcumin delivery.

Composite protein and inorganic nanodelivery systems can realise a pH-responsive release and effectively improve the stability and anti-cancer proliferative activity of hydrophobic molecules. In this study, a novel core-shell structure of NaCas (Sodium Caseinate)@CaP (Calcium Phosphate) as a nanodelivery system with NaCas as the core for increasing solubility and CaP as the shell for enhanced stability was built. By using Cur (Curcumin) as a model bioactive molecule, (Cur@NaCas)@CaP nanoparticles (NPs) demonstrated a uniform size distribution of 150-200 nm with a distinct nano-composite structure. After exposure to 80 °C for 2 h, the NaCas@CaP loaded Cur still retained 80% stability while under the same conditions only 12% of free Cur remained intact. UV-light stability was remarkably enhanced 8.56 fold by the protection of the core-shell structure. More importantly, pH-responsive release was achieved owing to the CaP surface coating. The encapsulated Cur by NaCas@CaP NPs exhibited an enhanced cellular anti-oxidant activity (CAA) based on MGC-803 cell monolayer models. The confocal laser-scanning microscopy (CLSM) images and cancer-cell-proliferation assay illustrated that (Cur@NaCas)@CaP NPs showed significantly improvements of cellular uptake and anti-cancer activity against A549 cancer cells than free Cur. These novels core-shell NaCas@CaP NPs are very promising for intensifying the stability and bioactivity of hydrophobic compounds in drug delivery and cancer treatment.

Isolation and Identification of Anthocyanin Component in the Fruits of Acanthopanax Sessiliflorus (Rupr. & Maxim.) Seem. by Means of High Speed Counter Current Chromatography and Evaluation of Its Antioxidant Activity.

Acanthopanax sessiliflorus (Rupr. & Maxim.) Seem. (Araliaceae) is one of the most abundant species of genus Acanthopanax. The fruits of A. sessiliflorus are used in traditional medical protocols as an analgesic, tonic, antidiabetic, antihypertensive, anti-inflammatory, antitumor, and immune-stimulating agent. In this work, we carried out a comprehensive investigation into the anthocyanin components in the fruits of A. sessiliflorus. The anthocyanin content in the fresh fruits of A. sessiliflorus was determined by high performance liquid chromatography-diode array detection (HPLC/DAD), and the anthocyanin component was isolated from these using high-speed counter-current chromatography (HSCCC) and elucidated by electro-spray ionization-mass spectrometry (ESI/MS), 1H- and 13C-NMR. Its antioxidant activity was evaluated by ferric-reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). We found that A. sessiliflorus contained a gross anthocyanin content of 121.35 mg/100 g. HSCCC was successfully used for separation and purification of the primary anthocyanin component, cyanidin 3-xylosyl-galactoside. The antioxidant and radical scavenging tests indicated that cyanidin 3-xylosyl-galactoside is a potent antioxidant.

Volatile and phenolic profiles of traditional Romanian apple brandy after rapid ageing with different wood chips.

The aim of this work was to find differences in the volatile and phenolic profiles of the traditional Romanian apple brandy palinca aged with various species of wood chips. Seven types of wood species, two types of oak (Quercus petraea and Quercus robur), plus sweet chestnut, mulberry, walnut, fir and cherry, were considered. The majority of volatile compounds characterizing the aroma profile of palinca were esters, particularly ethyl esters, with ethyl isobutyrate, ethyl isovalerate, ethyl caproate, ethyl octanoate and ethyl decanoate as the most abundant. The most important source of catechin was cherry wood. Rutin and juglone were solubilised only in walnut wood aged brandy. Vanillin, increased significantly in chestnut aged apple brandy. Given the cost and difficulty in handling wooden barrels, and as an alternative being able to select from a range of specific wooden chips, this work could potentially guide actors in beverage industry to less expensive alternatives.

Enhanced Cordycepin Production in Caterpillar Medicinal Mushroom, Cordyceps militaris (Ascomycetes), Mutated by a Multifunctional Plasma Mutagenesis System.

A multifunctional plasma mutation system (MPMS) method was used to create high cordycepin-yielding mutations from wild Cordyceps militaris, which yielded many viable mutants, many of which produced more cordycepin compared to the wild strain. One particular mutant strain (GYS60) produced 7.883 mg/mL, which is much higher than those reported to date and is more than 20 times higher than that of the wild strain, whereas the cordycepin production of another viable mutant (GYS80) was almost zero. The extraction and purification of cordycepin, using the fermentation broth of C. militaris GYS60, was also investigated. Cordycepin was extracted by using AB-8 macroporous resin and purified by using reversed-phase column chromatography. When the sample was adsorbed onto the macroporous resin, 20% ethanol was used as the desorption solvent yielding various fractions. The fractions containing cordycepin were loaded onto a reversed-phase chromatography column packed with octadecyl bonded silica as the stationary phase and ethanol (95%)/acetic acid solution (5%) at pH 6.0 as the mobile phase. The combination of this two-step extraction-purification process yielded cordycepin at 95% purity with a total recovery rate of 90%.

Crystal-Seeded Growth of pH-Responsive Metal-Organic Frameworks for Enhancing Encapsulation, Stability, and Bioactivity of Hydrophobicity Compounds.

Zeolitic imidazolate framework-L (ZIF-L) could effectively improve the stability, controlled release, and anticancer activity of natural hydrophobicity drugs in drug delivery systems (DDSs). A simple and universal strategy was developed to prepare the curcumin-loaded ZIF-L (CCM@ZIF-L) by the antisolvent coprecipitation method, which was different from the traditional approaches. The microcrystal molecules of curcumin were used as the core of ZIF-L growth to form CCM@ZIF-L, which has a very high drug encapsulation efficiency of 98.21% and a regular leaf or cruciate flower-like structure. The formation of CCM@ZIF-L with a distinct composite structure was supported by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared, powder X-ray diffraction, and zeta-potential. Because of the protective effect of ZIF-L, CCM@ZIF-L exhibited excellent stability and about a 5-fold increase in temperature stability over free curcumin. CCM@ZIF-L exhibited controlled drug release behavior in simulated in vitro tumor microenvironments (almost 81.2% drug release over a period of 72 h). Furthermore, confocal laser scanning microscopy results and cytotoxicity experiments confirmed that the encapsulated curcumin showed a significant improvement in cellular uptake and anticancer activity against A549 cancer cells. Moreover, the curcumin encapsulated in ZIF-L exhibited remarkable cellular antioxidant activity based on MGC-803 cell models. This work presents a novel approach to solve the drug loading problem by employing ZIF-L and exhibits enormous potential of ZIF-L as an effective DDS in cancer treatments.

Ontario Menu Calorie Labelling Legislation: Consumer Calorie Knowledge Six Months Post-Implementation.

PURPOSE: In the province of Ontario, a new law requires restaurants and food service providers, with more than 20 locations in Ontario, to prominently list the calorie content of their food items on the menu. This study examined if the new calorie information shifted the Ontario consumer's ability to more accurately estimate calories. METHODS: Using an online survey, consumers (n = 665 non-Ontario control and n = 694 Ontario) were asked to estimate the calories of a popular menu item (a cheeseburger) prior to this new legislation and 3 months and 6 months after the introduction of the mandated calorie labels on menus. RESULTS: Early results suggest that one cannot yet see a clear overall change in the Ontario consumer's ability to estimate calories (based on 1 popular food item) since the introduction of mandated calorie labels on menus, although the most recent survey data suggest promise. CONCLUSIONS: Consumers, not just in Ontario, are poor at estimating calories. Repeated exposure to the calorie information now posted on most Ontario fast-food menus is an educational initiative expected to show benefits in the future, but additional time is required for measurable increases in consumer knowledge.

ß-Lactoglobulin as a Nanotransporter for Glabridin: Exploring the Binding Properties and Bioactivity Influences.

Based on the fact that ß-lactoglobulin (ß-lg) can solubilize readily in water and bind many small hydrophobic molecules, a novel nanocomplexed glabridin with ß-lg was developed by an antisolvent precipitation method. After binding to ß-lg, the solubility of glabridin in aqueous solution was enhanced 21 times. Fluorescence spectroscopy of ß-lg revealed that the interaction of glabridin with ß-lg made the environment of Trp and Tyr residues on ß-lg more hydrophilic. The morphology and crystal form of the nanocomplexed glabridin with ß-lg was characterized and the changes in ß-lg conformation was also been investigated. In combination with molecular docking modeling, the results revealed that glabridin was bound to ß-lg by hydrophobic forces and hydrogen-bond interactions. Furthermore, the nanocomplexed glabridin with ß-lg had a better 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid radical-scavenging capacity compared to free glabridin at the same concentration during in vitro tests. Thus, nanocomplexing with ß-lg, by virtue of its ability to enhance the solubility of glabridin in aqueous systems, provides a suitable opportunity as a nanocarrier molecule.

Dirty Money: A Matter of Bacterial Survival, Adherence, and Toxicity.

In this study we report the underlying reasons to why bacteria are present on banknotes and coins. Despite the use of credit cards, mobile phone apps, near-field-communication systems, and cryptocurrencies such as bitcoins which are replacing the use of hard currencies, cash exchanges still make up a significant means of exchange for a wide range of purchases. The literature is awash with data that highlights that both coins and banknotes are frequently identified as fomites for a wide range of microorganisms. However, most of these publications fail to provide any insight into the extent to which bacteria adhere and persist on money. We treated the various currencies used in this study as microcosms, and the bacterial loading from human hands as the corresponding microbiome. We show that the substrate from which banknotes are produced have a significant influence on both the survival and adherence of bacteria to banknotes. Smooth, polymer surfaces provide a poor means of adherence and survival, while coarser and more fibrous surfaces provide strong bacterial adherence and an environment to survive on. Coins were found to be strongly inhibitory to bacteria with a relatively rapid decline in survival on almost all coin surfaces tested. The inhibitory influence of coins was demonstrated through the use of antimicrobial disks made from coins. Despite the toxic effects of coins on many bacteria, bacteria do have the ability to adapt to the presence of coins in their environment which goes some way to explain the persistent presence of low levels of bacteria on coins in circulation.

Thiamin analysis in red wine by fluorescence reverse phase-HPLC.

The derivatization of thiamin vitamers to their respective thiochrome by ferricyanide to facilitate fluorescence detection following separation by HPLC provides a powerful analytical tool. However the polyphenolic compounds in red wine readily interact with ferricyanide, reducing the effectiveness of ferricyanide oxidation in the derivatization of thiamin. We describe a method to facilitate the removal of polyphenolic compounds that interfere with the ferricyanide derivatization of thiamin. Polyvinylpolypyrrolidone afforded the total removal of phenolic compounds from red wines and allowed a spike recovery of thiamin vitamers (101% for thiamin; 104% for TMP; and 100% for TDP) in a wide range of red wines. This research found that Merlot styles of red wine contained the highest concentration of total thiamin (29.01 ng/mL) while Pinot Noir wines contained the lowest total concentration (8.27 ng/mL).

Preparation of organogel with tea polyphenols complex for enhancing the antioxidation properties of edible oil.

Food-grade organogels are semisolid systems with immobilized liquid edible oil in a three-dimensional network of self-assembled gelators, and they are supposed to have a broad range of potential applications in food industries. In this work, an edible organogel with tea polyphenols was developed, which possesses a highly effective antioxidative function. To enhance the dispersibility of the tea polyphenols in the oil phase, a solid lipid-surfactant-tea polyphenols complex (organogel complex) was first prepared according to a novel method. Then, a food-grade organogel was prepared by mixing this organogel complex with fresh peanut oil. Compared with adding free tea polyphenols, the organogel complex could be more homogeneously distributed in the prepared organogel system, especially under heating condition. Furthermore, the organogel loading of tea polyphenols performed a 2.5-fold higher antioxidation compared with other chemically synthesized antioxidants (butylated hydroxytoluene and propyl gallate) by evaluating the peroxide value of the fresh peanut oil based organogel in accelerated oxidation conditions.

Preparation and stabilization of D-limonene Pickering emulsions by cellulose nanocrystals.

The aim of this study was to investigate D-limonene Pickering emulsion stabilized by cellulose nanocrystals (CNCs) and factors that may affect its properties. CNCs were prepared by ammonium persulfate hydrolysis of corncob cellulose, and D-limonene Pickering emulsions were generated by ultrasonic homogenizing method. The morphology and size of the prepared emulsions with different CNCs concentrations were studied by optical microscopy and laser light diffraction. In addition, factors that may affect the stability of emulsions such as ionic concentration, pH and temperature were also studied. As indicated by the experiment data, when temperature rose, the stability to of emulsions would be increased, and the stability of emulsions was reduced with low pH or high salt concentration due to electrostatic screening of the negatively charged CNC particles. In conclusion, high stability of D-limonene Pickering emulsions could be obtained by CNCs.

Effects of nisin on the antimicrobial activity of d-limonene and its nanoemulsion.

d-Limonene has been considered to be a safer alternative compared to synthetic antimicrobial food additives. However, its hydrophobic and oxidative nature has limited its application in foods. The purpose of this research was to study effects of nisin on the antimicrobial activity of d-limonene and its nanoemulsion and develop a novel antimicrobial delivery system by combining the positive effect of these two antibacterial agents at the same time. By the checkerboard method, both the synergistic and additive effects of d-limonene and nisin were found against four selected food-related microorganisms. Then, d-limonene nanoemulsion with or without nisin was prepared by catastrophic phase inversion method, which has shown good droplet size and stability. The positive effects and outstanding antimicrobial activity of d-limonene nanoemulsion with nisin were confirmed by MICs comparison, scanning electron microscopy and determination of cell constituents released. Overall, the research described in the current article would be helpful in developing a more effective antimicrobial system for the production and preservation of foods.