Safety evaluation of aflatoxin B1in peanut oil after ultraviolet irradiation detoxification in a photodegradation reactor

Conventional and non-conventional disinfection methods to prevent microbial contamination in minimally processed fruits and vegetables

Pandemic COVID-19 warned the importance of preparing the immune system to prevent diseases. Therefore, consuming fresh fruits and vegetables is essential for a healthy and balanced diet due to their diverse compositions of vitamins, minerals, fiber, and bioactive compounds. However, these fresh products grew close to manure and irrigation water and are harvested with equipment or by hand, representing a high risk of microbial, physical, and chemical contamination. The handling of fruits and vegetables exposed them to various wet surfaces of equipment and utensils, an ideal environment for biofilm formation and a potential risk for microbial contamination and foodborne illnesses. In this sense, this review presents an overview of the main problems associated with microbial contamination and the several chemicals, physical, and biological disinfection methods concerning their ability to avoid food contamination. This work has discussed using chemical products such as chlorine compounds, peroxyacetic acid, and quaternary ammonium compounds. Moreover, newer techniques including ozone, electrolyzed water, ultraviolet light, ultrasound, high hydrostatic pressure, cold plasma technology, and microbial surfactants have also been illustrated here. Finally, future trends in disinfection with a sustainable approach such as combined methods were also described. Therefore, the fruit and vegetable industries can be informed about their main microbial risks to establish optimal and efficient procedures to ensure food safety.

Investigation of UV light treatment (254 nm) on the reduction of aflatoxin M1 in skim milk and degradation products after treatment

This study investigates the reduction of aflatoxin M1 (AFM1) in skim milk by using ultraviolet light at 254 nm and the effects of influencing factors on the efficacy including treatment time (min), depth of samples (mm), contamination level (μg L^-1), stirring, temperature, and fat content in milk. The colour and pH of milk samples were measured to evaluate the influence of the treatment on these values. It was found that short-wave ultraviolet radiation (UVC) reduced up to 50% of AFM1 in milk after 20 min of treatment regardless of the initial AFM1 contamination level. Treatment time, depth of samples, and stirring were all found to significantly (P < 0.05) enhance the reduction of AFM1. The milk colour was affected but there was no influence on the pH of milk samples at any duration of UV exposure. It is concluded that UVC light treatment has the potential to reduce AFM1 in milk.

Evaluation of nano-silica, microwave heating, and ultraviolet irradiation effects on zearalenone detoxification in sunflower oils

In the present study, we report three methods of silica nanoparticles (SNPs) as adsorbent, ultraviolet (UV) irradiation, and microwave heating and evaluate their capabilities in reducing and eliminating zearalenone (ZEN). The offered method not only was used for ZEN detoxification, but also greatly enhanced the sensitivity of ZEN measurement. The aim of this study was to evaluate ZEN concentration in sunflower oil samples by high-performance liquid chromatography (HPLC) method. This method was successfully validated for sunflower oil samples while the limit of detection (LOD) method (signal-to-noise ratio of 3:1) was 0.5 μg/l. The acquired removal data with the HPLC method through SNPs were fitted well with Freundlich isotherm, denoting that the multi-layer adsorption took place on the adsorbent. The equilibrium adsorption capacity of ZEN was 61.02 μg/g in an optimum time of 240 min on SNPs. The experimental results were evaluated by the adsorption kinetic model, which specified the adsorption kinetics of ZEN on SNPs, obeying the pseudo-second order model. This model demonstrated that the sorption rate depended on the sorption capacity but not the concentration of the sorbate. Moreover, the method presented to determine ZEN based on the use of SNPs in sunflower oil was accomplished by the adsorption process. Furthermore, the removal efficiencies of ZEN by SNPs, UV irradiation, and microwave heating were compared and obtained to be 92.1, 96.22, and 37.30%, respectively for determined times. These results confirm the removal efficiency of these methods is sensitive enough to ZEN analysis in sunflower oil samples.

Synthesis of Rice Husk-Based MCM-41 for Removal of Aflatoxin B1 from Peanut Oil

Edible oils, especially peanut oil, usually contain aflatoxin B₁ (AFB₁) at extremely high concentrations. This study focused on the synthesis of rice husk-based mesoporous silica (MCM-41) for the removal of AFB₁ from peanut oil. MCM-41 was characterized by X-ray diffraction, N₂ physisorption, and transmission electron microscope. MCM-41 was shown to have ordered channels with high specific surface area (1246 m²/g), pore volume (1.75 cm³/g), and pore diameter (3.11 nm). Under the optimal concentration of 1.0 mg/mL of the adsorbent dose, the adsorption behavior of MCM-41, natural montmorillonite (MONT), and commercial activated carbon (CA) for AFB₁ were compared. The adsorption of AFB₁ in peanut oil onto the three adsorbents was slower compared to that of AFB₁ in an aqueous solution. In addition, the pseudo-second-order kinetic model better fit the adsorption kinetics of AFB_1, while the adsorption mechanism followed the Langmuir adsorption isotherm on the three adsorbents. The calculated maximum adsorbed amounts of AFB₁ on MONT, MCM-41, and CA were 199.41, 215.93, and 248.93 ng/mg, respectively. These results suggested that MCM-41 without modification could meet market demand and could be considered a good candidate for the removal of AFB₁ from peanut oil. This study provides insights that could prove to be of economic and practical value.

UV treatment for degradation of chemical contaminants in food: A review

Application of ultraviolet (UV) irradiation for the degradation of chemical contaminants in food products has gained more and more interest in the past two decades. The majority of the research in this field was on mycotoxins, especially aflatoxins and patulin, with limited studies on pesticide residues and other chemical contaminants in food. These studies have been focused on identifying the structure and toxicity of degradation products, investigating the influence of UV treatment factors on the degradation efficiency, determining the impact of UV treatment on the quality of food products, and developing updated UV treatment methods such as TiO₂ induced photocatalytic degradation. The summary of published literatures provided insights into future research opportunities in this area, which include determining a standard for the UV treatment description, working with naturally contaminated samples rather than artificially spiked samples, conducting pilot plant or industrial scale studies, examining more targets and conducting multi-targets studies, and developing more innovative methods for UV treatment.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Postharvest UV-C irradiation for fungal control and reduction of mycotoxins in brown, black, and red rice during long-term storage

The formation of fungal colonies, mycotoxins, phenolic compounds, cooking quality and color properties were evaluated in freshly-harvested brown, black, and red rice grains and then subjected to ultraviolet radiation (UV-C) for 1 and 3 h. Assessments were made after 6 months of storage. The exposure of black and red rice at 1 h of UV-C was enough to decrease the presence of fungal colonies by 22% and 79%, respectively, without any changes in cooking and coloring properties. In brown rice, only 3 h of UV-C irradiation was able to reduce the formation of fungal colonies. The release of phenolic compounds associated with cell wall was observed only in black and red rice subjected to UV-C radiation. The levels of mycotoxins gradually decreased with the increase in the time of exposure to UV-C radiation, demonstrating UV-C irradiation to be an effective method in fungal control and reduction of mycotoxins in stored rice.

Performance of a UV-A LED system for degradation of aflatoxins B1 and M1 in pure water: kinetics and cytotoxicity study

The efficacy of a UV-A light emitting diode system (LED) to reduce the concentrations of aflatoxin B₁, aflatoxin M₁ (AFB₁, AFM₁) in pure water was studied. This work investigates and reveals the kinetics and main mechanism(s) responsible for the destruction of aflatoxins in pure water and assesses the cytotoxicity in liver hepatocellular cells. Irradiation experiments were conducted using an LED system operating at 365 nm (monochromatic wave-length). Known concentrations of aflatoxins were spiked in water and irradiated at UV-A doses ranging from 0 to 1,200 mJ/cm². The concentration of AFB₁ and AFM₁ was determined by HPLC with fluorescence detection. LC–MS/MS product ion scans were used to identify and semi-quantify degraded products of AFB₁ and AFM₁. It was observed that UV-A irradiation significantly reduced aflatoxins in pure water. In comparison to control, at dose of 1,200 mJ/cm² UV-A irradiation reduced AFB₁ and AFM₁ concentrations by 70 ± 0.27 and 84 ± 1.95%, respectively. We hypothesize that the formation of reactive species initiated by UV-A light may have caused photolysis of AFB₁ and AFM₁ molecules in water. In cell culture studies, our results demonstrated that the increase of UV-A dosage decreased the aflatoxins-induced cytotoxicity in HepG2 cells, and no significant aflatoxin-induced cytotoxicity was observed at UV-A dose of 1,200 mJ/cm². Further results from this study will be used to compare aflatoxins detoxification kinetics and mechanisms involved in liquid foods such as milk and vegetable oils.

Aflatoxin in foodstuffs: Occurrence and recent advances in decontamination

Aflatoxins are highly toxic compounds produced as secondary metabolites by some Aspergillus species, whose occurrence have been reported predominantly in several types of foods of low moisture content, while aflatoxin biotransformation products have been reported mainly in milk and milk products. This review deals with the occurrence of aflatoxins in some of the major food products in the last 5 years including regulatory aspects, and recent advances in detoxification strategies for contaminated foods. Aflatoxin contamination in cereals including corn and peanut is still a public health problem for some populations, especially in African countries. Despite that most of physical and chemical methods for aflatoxin detoxification may affect the nutritional properties of food, or are not safe for human consumption, gamma-radiation and ozone applications have demonstrated great potential for detoxification of aflatoxins in some food matrices. Biological methods based on removal or degradation of aflatoxins by bacterial and yeast have good perspectives, although further studies are needed to clarify the detoxification mechanisms by microorganisms and determine practical aspects of the use of these methods in food products, especially their potential effects on sensory characteristics of foods.

Aflatoxins in peanut oil: food safety concerns

Aflatoxins are widely recognised as important natural contaminants of a wide range of foods, including maize and peanuts (groundnuts), which form part of the staple diet in many countries of the developing world, especially in Africa. There is a frequent misconception based on solubility considerations and developed market surveys that aflatoxins do not occur in peanut oil. Thus, the use of peanut oil in human food is frequently overlooked as a source of aflatoxin exposure, yet artisanal oil extraction from contaminated peanuts in local facilities in the developing world results in carryover of these mycotoxins into the oil. Consequently, these peanut oils can have high contamination levels. This review highlights food safety concerns and addresses inter alia the analytical adaptations required to determine the polar aflatoxins in peanut oil. The determination of aflatoxins in peanut oil was first achieved by thin-layer chromatography, which was later mostly superseded by high-performance liquid chromatography (HPLC) with fluorescence detection, or later, by mass spectrometric detection. More recently, a specially modified HPLC method with immunoaffinity column clean-up and fluorescence detection has achieved official method status at AOAC International. In addition, the review deals with toxicology, occurrence and detoxification of contaminated oil. Although various methods have been reported for detoxification of peanut oil, the toxicity of degradation products, the removal of beneficial constituents and the effect on its organoleptic properties need to be considered. This review is intended to draw attention to this often overlooked area of food safety.

A large Raman scattering cross-section molecular embedded SERS aptasensor for ultrasensitive Aflatoxin B1 detection using CS-Fe3O4 for signal enrichment

With growing concern on oil safety problems, developing a simple and sensitive method to detect Aflatoxin B1 (AFB1), a common mycotoxin in peanut oil, is very necessary. In this study, Surface-enhanced Raman Scattering (SERS) aptasensor was developed for ultrasensitive AFB1 detection using the amino-terminal AFB1 aptamer (NH₂-DNA1); and thiol-terminal AFB1 complementary aptamer (SH-DNA2) conjugated magnetic-beads (CS-Fe₃O₄) as enrichment nanoprobe and AuNR@DNTB@Ag nanorods (ADANRs) as reporter nanoprobe respectively. 5,5'-Dithiobis(2-nitrobenzoicacid) (DNTB) with large Raman scattering cross-section and no fluorescence interference was embedded in Au and Ag core/shell nanorods as Raman reporter molecules. CS-Fe₃O₄ possessed excellent biocompatibility and superparamagnetism for rapid signal enrichment. Therefore, NH₂-DNA1-CS-Fe₃O₄ and SH-DNA2-ADANRs were fabricated via the hybrid reaction between aptamers and complementary aptamers. When there is AFB1, AFB1 would competitively combine with the NH₂-DNA1-CS-Fe₃O₄ inducing the dissociation of SH-DNA2-ADANRs from CS-Fe₃O₄ and further decreasing the SERS signal. Based on this developed SERS aptasensor, a low limit of 0.0036ng/mL and an effective linear detection range from 0.01 to 100ng/mL with the correlation coefficient up to 0.986 for AFB1 detection were obtained. Moreover, the specificity of this SERS aptasensor was demonstrated by detecting other two mycotoxins and its accuracy for AFB1 detection in real peanut oil was further confirmed by standard addition recovery test.

A Structure Identification and Toxicity Assessment of the Degradation Products of Aflatoxin B₁ in Peanut Oil under UV Irradiation

Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV) irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B₁ (AFB₁) in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS). The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB₁ in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB₁, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB₁ using UV detoxification.

Detoxification and safety evaluation of aflatoxin B1 in peanut oil using alkali refining

BACKGROUND

Aflatoxin B1 (AFB1 ) is often detected in peanut oil, which comes from contaminated peanuts. AFB1 in peanut oil seriously threatens the health of consumers. However, there are few methods to effectively remove AFB1 in peanut oil. This study aimed to use an alkali-refining method to degrade AFB1 in peanut oil efficiently without increasing the equipment of oil and fat refining.

RESULTS

The optimum detoxifying conditions of AFB1 in peanut oil with alkali refining were established using response surface methodology (RSM), and the safety of peanut oil after being refined with alkali was evaluated based on the Ames tests and HepG2 cell viability. The results showed that AFB1 in peanut oil was decreased from 34.78 to 0.37 µg kg(-1) (98.94% reduction) under the optimum detoxifying conditions, i.e. when the initial temperature of alkali refining was 43.51 °C, the amount of excess alkali was 0.30%, the content of alkali solution was 23.42% and the end temperature of alkali refining was 77.07 °C. The acid value and color of peanut oil refined by alkali were improved significantly, while the peroxide value was increased within an acceptable level. The safety of peanut oil contaminated by AFB1 was improved significantly after being refined with alkali.

CONCLUSION

These results indicate that alkali refining is an effective method for removing AFB1 in peanut oil. The optimum detoxifying conditions of AFB1 in peanut oil with alkali refining could be used to guide the production of oil companies for ensuring food safety. © 2015 Society of Chemical Industry.