Recent advances in antimicrobial applications of curcumin-mediated photodynamic inactivation in foods

Improving the storage quality of Harbin red sausages by quaternized chitosan/sodium alginate coating curcumin nano-emulsion

In this study, the effect of sodium alginate and quaternized chitosan bis-polysaccharide-based shell transport curcumin nano-emulsions (Cur@QCS/SA) on the microbiological, physicochemical properties, quality characteristics of Harbin red sausage during storage is investigated. According to the microbiological results, the shelf life of Harbin red sausage is extended from 3 d to 6 d by adding 0.15% Cur@QCS/SA, and Bacillus is the most predominant bacterial before 6 d. Additionally, the physicochemical properties change significantly, the pH, weight loss (WL), water holding capacity (WHC), water activity (aw), L*, and a* of red sausage decrease gradually with the extension of storage time, as well as b*, lipid oxidation, proteolysis increase significantly (P < 0.05). Secondly, it is found that 0.15% treatment group can better maintain the quality characteristics of Harbin red sausage according to texture profile analysis (TPA), electronic nose (E-nose), and electronic tongue (E-tongue) (P < 0.05). This study provides a new way for nano-emulsions in food applications and a new option for the preservation of Harbin red sausage as well as other low-temperature meat products.

Enhanced photodynamic inactivation against Escherichia coli O157:H7 provided by chitosan/curcumin coating and its application in food contact surfaces

Sterilisation technologies are essential to eliminate foodborne pathogens from food contact surfaces. However, most of the current sterilisation methods involve high energy and chemical consumption. In this study, a photodynamic inactivation coating featuring excellent antibacterial activity was prepared by dispersing curcumin as a plant-based photosensitiser in a chitosan solution. The coating generated abundant reactive oxygen species (ROS) after light irradiation at 420 nm, which eradicated ≥99.999 % of Escherichia coli O157:H7. It was also found that ROS damaged the cell membrane, leading to the leakage of cell contents and cell shrinkage on the basis of chitosan. In addition, the production of ROS first excited the bacterial antioxidant defence system resulting in the increase of peroxidase (POD) and superoxide dismutase (SOD). ROS levels exceed its capacity, causing damage to the defence system and further oxidative decomposition of large molecules, such as DNA and proteins, eventually leading to the death of E. coli O157:H7. We also found the curcumin/chitosan coating could effectively remove E. coli O157:H7 biofilms by oxidative of extracellular polysaccharides and proteins. All the contributors made the chitosan/curcumin coating an efficient detergent comparable with HClO.

Novel Halogenated Curcumin-Mediated Photodynamic Inactivation for the Preservation of Small Yellow Croaker (Larimichthys polyactis)

A novel class of halogenated curcumin, X-Cur (X = F, Cl, or Br), was synthesized, and its photosensitivity was evaluated. The results showed that Br-Cur with the highest singlet oxygen (1O2) generation capacity exhibited a better photodynamic inactivation (PDI) effect on the small yellow croaker (Larimichthys polyactis) than curcumin. This was attributed to the heavy atom effect of Br, which resulted in Br-Cur having the smallest singlet-triplet energy difference ΔEst(S1-T3) (0.140 eV) and the largest spin-orbit coupling value (0.642262 cm-1). When L. polyactis was treated with 0.025 wt % Br-Cur and exposed to blue LED irradiation (450 nm, 20 mW/cm2) for 20 min, the increase in the total volatile basic nitrogen content (28.23 ± 2.38 mg/100 g on day 6), pH, and total viable count (6.13 ± 0.06 log CFU/g on day 6) could be effectively controlled. Accordingly, Br-Cur is a promising photosensitizer for PDI preservation.

Thermosensitive curcumin/silver/montmorillonite-F127 hydrogels with synergistic photodynamic/photothermal/silver ions antibacterial activity

Bacterial infections and the emergence of super-resistant bacteria pose a significant risk to human health. Effective sterilization to prevent the development of bacterial drug resistance remains a challenge. Herein, curcumin/silver/montmorillonite (Cur/Ag/Mt) was prepared through a green chemical reduction method with montmorillonite as the carrier, curcumin as the reducing agent and the capping agent, and citric acid as the structure guide agent. Then, a novel dual light-responsive and thermosensitive Pluronic F127-based hydrogel (CAM-F) was prepared by encapsulating Cur/Ag/Mt within the F127 hydrogel. The Cur/Ag/Mt showed strong absorption in the near-infrared region that efficiently converts light into heat for photothermal therapy when the molar ratio of curcumin to silver nitrate was 2 : 1. Specifically, triangular silver nanoparticles reduced by curcumin were immobilized on the Mt layers, which could enhance photodynamic therapy by the metal-enhanced singlet oxygen and metal-enhanced fluorescence mechanisms. Upon combining 405 nm and 808 nm laser irradiation, the CAM-F hydrogel could simultaneously generate reactive oxygen species, increase the local temperature, and sustain the release of Ag+, thus displaying excellent bactericidal performance against Gram-negative and Gram-positive bacteria. The antibacterial rates of CAM-F hydrogels were 99.26 ± 0.95% and 99.95 ± 0.98% for Escherichia coli and Staphylococcus aureus, respectively. The findings suggest the potential of the CAM-F hydrogel as a stable, biologically safe, and broad-spectrum antimicrobial material. The thermosensitive CAM-F hydrogels for synergetic phototherapy may provide a promising strategy for solving clinical problems caused by pathogenic infections.

Research on Food Preservation Based on Antibacterial Technology: Progress and Future Prospects

The nutrients present in food are not only prone to a series of physicochemical reactions but also provide conditions for the growth and reproduction of foodborne microorganisms. In recent years, many innovative methods from different fields have been introduced into food preservation, which extends the shelf life while maximizing the preservation of the original ingredients and properties of food. In this field, there is a lack of a systematic summary of new technologies emerging. In view of this, we overview the innovative methods applied to the field of food preservation in recent 3 years, focusing on a variety of technological approaches such as antimicrobial photodynamic therapy based on nanotechnology, electromagnetic radiation sterilization based on radiation technology, and antimicrobial peptides based on biomolecules. We also discuss the preservation mechanism and the application of the different methods to specific categories of products. We evaluated their advantages and limitations in the food industry, describing their development prospects. In addition, as microorganisms are the main causes of food spoilage, our review also has reference significance for clinical antibacterial treatment.

Curcumin-based residue-free and reusable photodynamic inactivation system for liquid foods and its application in freshly squeezed orange juice

To enhance curcumin's application in photodynamic inactivation (PDI) of liquid foods, a supramolecular complex of biotin-modified β-cyclodextrin and curcumin (Biotin-CD@Cur) was synthesized. This complex significantly improves curcumin's solubility, stability, and PDI efficiency. Following PDI, Biotin-CD@Cur can be magnetically separated from the liquid matrix using streptavidin-coated magnetic beads (SA-MBs). Leveraging the reversible binding between streptavidin and biotin, Biotin-CD@Cur and SA-MBs fully dissociate in ultrapure water at 70 °C, enabling reuse. Antibacterial tests in freshly squeezed orange juice demonstrated that a low dose of 1.5 J/cm2 from a 420 nm LED array and 10 μg/mL of Biotin-CD@Cur achieved log reductions of 3.287 ± 0.015 for Staphylococcus aureus and 2.961 ± 0.011 for Listeria monocytogenes, while preserving the juice's flavor and nutritional contents. The PDI system remained effective for at least four cycles. Ultra-performance liquid chromatography and atomic absorption spectroscopy confirmed no residues of system components in the juice after magnetic separation.

Curcumin-loaded food-grade nano-silica hybrid material exhibiting improved photodynamic effect and its application for the preservation of small yellow croaker (Larimichthys polyactis)

Two types of curcumin-loaded food-grade nano-silica (F-SiO2) hybrid materials were successfully synthesized using the rotary evaporation method (F-SiO2@Cur) and the adsorption method (Cur@F-SiO2). The microstructure and spectral analyses confirmed that the curcumin in F-SiO2@Cur was loaded within the nanopores in a non-aggregate form rather than being adsorbed onto the surface (Cur@F-SiO2). Additionally, F-SiO2@Cur exhibited remarkable water solubility (1510 ± 50.33 µg/mL) and photostability (a photodegradation ratio of only 59.22 %). Importantly, F-SiO2@Cur obtained a higher capacity for the generation of singlet oxygen (1O2) compared to control groups. Consequently, F-SiO2@Cur-mediated photodynamic inactivation (PDI) group attained the highest score in sensory evaluation and the best color protection effect in PDI experiment of small yellow croaker (Larimichthys polyactis) at 4 °C. Moreover, F-SiO2@Cur could effectively controlled total volatile basic nitrogen (TVB-N) content, pH, and total viable count (TVC), thereby prolonging the shelf life. Therefore, F-SiO2@Cur-mediated PDI is an effective fresh-keeping technology for aquatic products.

Medical properties, market potential, and microbial production of golden polyketide curcumin for food, biomedical, and cosmetic applications

Curcumin, a potent plant polyketide in turmeric, has gained recognition for its outstanding health benefits, including anti-inflammatory, antioxidant, and anticancer effects. Classical turmeric farming, which is widely used to produce curcumin, is linked to deforestation, soil degradation, excessive water use, and reduced biodiversity. In recent years, the microbial synthesis of curcumin has been achieved and optimized through novel strategies, offering increased safety, improved sustainability, and the potential to revolutionize production. Here, we discuss recent breakthroughs in microbial engineering and fermentation techniques, as well as their capacity to increase the yield, purity, and cost-effectiveness of curcumin production. The utilization of microbial systems not only addresses supply chain limitations but also helps meet the growing demand for curcumin in various industries, including pharmaceuticals, foods, and cosmetics.

Ozone and photodynamic inactivation of norovirus surrogate bacteriophage MS2 in fresh Brazilian berries and surfaces

This study assessed the efficacy of ozone (bubble diffusion in water; 6.25 ppm) and photodynamic inactivation (PDT) using curcumin (75 μM) as photosensitizer (LED emission 430-470 nm; 33.6 mW/cm2 irradiance; 16.1, 20.2, and 24.2 J/cm2 light dose) against the Norovirus surrogate bacteriophage MS2 in Brazilian berries (black mulberry and pitanga) and surfaces (glass and stainless steel). Contaminated berries and surfaces were immersed in ozonized water or exposed to PDT-curcumin for different time intervals. Transmission electron microscopy was used to assess the effects of the treatments on MS2 viral particles. The MS2 inactivation by ozone and PDT-curcumin varied with the fruit and the surface tested. Ozone reduced the MS2 titer up to 3.6 log PFU/g in black mulberry and 4.1 log PFU/g in pitanga. On surfaces, the MS2 reduction by ozone reached 3.6 and 4.8 log PFU/cm2 on glass and stainless steel, respectively. PDT-curcumin reduced the MS2 3.2 and 4.8 log PFU/g in black mulberry and pitanga and 2.7 and 3.3 log PFU/cm2 on glass and stainless steel, respectively. MS2 particles were disintegrated by exposure of MS2 to ozone and PDT-curcumin on pitanga. Results can contribute to establishing effective practices for controlling NoV in fruits and surfaces, estimated based on MS2 bacteriophage behavior.

Photodynamic Inactivation of Foodborne Bacteria: Screening of 32 Potential Photosensitizers

The development of novel antimicrobial technologies for the food industry represents an important strategy to improve food safety. Antimicrobial photodynamic disinfection (aPDD) is a method that can inactivate microbes without the use of harsh chemicals. aPDD involves the administration of a non-toxic, light-sensitive substance, known as a photosensitizer, followed by exposure to visible light at a specific wavelength. The objective of this study was to screen the antimicrobial photodynamic efficacy of 32 food-safe pigments tested as candidate photosensitizers (PSs) against pathogenic and food-spoilage bacterial suspensions as well as biofilms grown on relevant food contact surfaces. This screening evaluated the minimum bactericidal concentration (MBC), minimum biofilm eradication concentration (MBEC), and colony forming unit (CFU) reduction against Salmonella enterica, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas fragi, and Brochothrix thermosphacta. Based on multiple characteristics, including solubility and the ability to reduce the biofilms by at least 3 log10 CFU/sample, 4 out of the 32 PSs were selected for further optimization against S. enterica and MRSA, including sunset yellow, curcumin, riboflavin-5'-phosphate (R-5-P), and erythrosin B. Optimized factors included the PS concentration, irradiance, and time of light exposure. Finally, 0.1% w/v R-5-P, irradiated with a 445 nm LED at 55.5 J/cm2, yielded a "max kill" (upwards of 3 to 7 log10 CFU/sample) against S. enterica and MRSA biofilms grown on metallic food contact surfaces, proving its potential for industrial applications. Overall, the aPDD method shows substantial promise as an alternative to existing disinfection technologies used in the food processing industry.

Advancements in nonthermal physical field technologies for prefabricated aquatic food: A comprehensive review

Aquatic foods are nutritious, enjoyable, and highly favored by consumers. In recent years, young consumers have shown a preference for prefabricated food due to its convenience, nutritional value, safety, and increasing market share. However, aquatic foods are prone to microbial spoilage due to their high moisture content, protein content, and unsaturated fatty acids. Furthermore, traditional processing methods of aquatic foods can lead to issues such as protein denaturation, lipid peroxidation, and other food safety and nutritional health problems. Therefore, there is a growing interest in exploring new technologies that can achieve a balance between antimicrobial efficiency and food quality. This review examines the mechanisms of cold plasma, high-pressure processing, photodynamic inactivation, pulsed electric field treatment, and ultraviolet irradiation. It also summarizes the research progress in nonthermal physical field technologies and their application combined with other technologies in prefabricated aquatic food. Additionally, the review discusses the current trends and developments in the field of prefabricated aquatic foods. The aim of this paper is to provide a theoretical basis for the development of new technologies and their implementation in the industrial production of prefabricated aquatic food.

Assessing Partial Inhibition of Ribonuclease A Activity by Curcumin through Fluorescence Spectroscopy and Theoretical Studies

Molecular interactions and controlled expression of enzymatic activities are fundamental to all cellular functions in an organism. The active polyphenol in turmeric known as curcumin (CCM) is known to exhibit diverse pharmacological activities. Ribonucleases (RNases) are the hydrolytic enzymes that plays important role in ribonucleic acid (RNA) metabolism. Uncontrolled and unwanted cleavage of RNA by RNases may be the cause of cell death leading to disease states. The protein ribonuclease A (RNase A) in the superfamily of RNases cleaves the RNA besides its role in different diseases like autoimmune diseases, and pancreatic disorders. Interaction of CCM with RNase A have been reported along with the possible role of CCM to inhibit the RNase A enzymatic activity. The interaction strength was found to be 104 M-1 order from spectroscopic results. Quenching of RNase A fluorescence by CCM was 104 M-1 order. Non-radiative energy transfer from RNase A (donor) to CCM (acceptor) suggested a distance of 2.42 nm between the donor-acceptor pair. Circular dichroism studies revealed no structural changes in RNase A after binding. Binding-induced conformational variation in protein was observed from synchronous fluorescence studies. Agarose gel electrophoresis revealed a partial inhibition of the RNase A activity by CCM though not significant. Molecular docking and molecular dynamics studies suggested the residues of RNase A involved in the interaction with supporting the experimental finding for the partial inhibition of the enzyme activity. This study may help in designing new CCM analogues or related structures to understand their differential inhibition of the RNase A activity.

A review of curcumin in food preservation: Delivery system and photosensitization

As a natural polyphenol, curcumin has been used as an alternative to synthetic preservatives in food preservation. Different from previous reviews that mainly focus on the pH-responsive discoloration of curcumin to detect changes in food quality in real time, this paper focuses on the perspective of the delivery system and photosensitization of curcumin for food preservation. The delivery system is an effective means to overcome the challenges of curcumin like instability, hydrophobicity, and low bioavailability. Curcumin as a photosensitizer can effectively sterilize to preserve food. The practical fresh-keeping effects of the delivery system and photosensitization of curcumin on foods (fruits/vegetables, animal-derived food, and grain) were summarized comprehensively, including shelf-life extension, maintenance of physicochemical properties, nutritional quality, and sensory. Future research should focus on the development of novel curcumin-loaded materials used for food preservation, and most importantly, the biosafety and accumulation toxicity associated with these materials should be explored.

Antimicrobial curcumin-mediated photodynamic inactivation of bacteria in natural bovine casing

BACKGROUND

Outbreaks related to food contamination by resistant microorganisms is a worldwide concern that, motivates industries and research institutions to search for affordable solutions. Among the solutions that have been proposed, Photodynamic Inactivation (PDI) of microorganisms has gained prominence, among other aspects, because it is easy to apply and does not generate microbial resistance.

METHODS

In this study, we used the association between curcumin solubilized with Tween and light in the photodynamic inactivation process, using light-emitting diodes with a wavelength of 430 nm for decontamination S. Typhimurium and K. pneumoniae from bovine casings used as wrappers for meat products. The result was verified by counting and comparing the number of colony-forming units of the treatment concerning the negative control.

RESULTS

The solubilizer, Tween 80, used does not change the optical absorption of curcumin. An optical fluence of 150J/cm² induces a microbial log reduction of 3.8±0.2 and 2.7±0.1 for S. Typhimurium, and K. pneumoniae contaminated guts, respectively. For the 200μM concentration of curcumin, the PDI provided a microbial log reduction of 3.16±0.03 for S. Typhimurium. For K. pneumoniae, the minimal inhibitory concentration of curcumin occurs up to 12.5μM, causing an microbial log reduction of 2.08±0.03.

CONCLUSION

Both curcumin and tween are already used as additives in food production and do not pose health risks at the concentrations used. Furthermore, in the case of the material studied, the addition of curcumin favors the organoleptic quality associated with the color of the food, unlike the green or blue photossensitizers. The results pave the way for possible application of curcumin in finished meat products.