نشریه بهداشت مواد غذایی
سال سیزدهم شماره 2 (پیاپی 50، تابستان 1402)

Paeonia officinalis L. is one of the species of the Paeoniaceae family. Its root has different effective compounds e.g., polyphenols, flavonoids, triterpenoids, tannins, and monoterpenes. It shows biological activities such as antibacterial, anti-oxidative, relaxing and anti-pain properties. This study evaluated the effect of three solvents, ethanol/water, water, and water/ethanol/hexane on extracting the active ingredients. These solvents were applied by the methods of immersion, immersion with ultrasonic waves, and the use of supercritical fluid carbon dioxide with auxiliary solvents. The efficiency, qualitative characteristics (pH, polyphenolic compounds and antioxidant properties) and antimicrobial properties of the extracts were evaluated by the well-diffusion method against Escherichia coli, Staphylococcus aureus, Salmonella Typhimurium and Candida albicans. Also, the MIC and MBC of the extracts on the activity of these organisms were determined. The results showed that the independent variables significantly affect the quantity and quality of the produced extracts (P ≤ 0.05). Using the water/ethanol, and the immersion method in combination with ultrasonic waves, the highest extract efficiency (17.66± 0.34), of the phenolic compounds (33.5±0.65) and antioxidant property (76±1.44) was obtained. The diameter of the inhibition zone for E. coli, S. aureus and C. albicans in the vicinity of this sample was more than others. Meanwhile, the inhibition zone of S. Typhimurium was larger in the presence of watery extract using the immersion method. The quantity and quality of the extract using supercritical fluid was lower than others.

Replacing naturally occurring bioactive substances, such as microbial metabolites, with synthetic preservative compounds, and getting access to their beneficial properties, is expanding every day. Meanwhile, the focus of many researchers' attention has been on bacteriocins, which have multiple physiological functions, including antibacterial and anticancer properties. In this study, the enterocin production genes of Enterococcus isolates from two fermented dairy products (Motal cheese and Tarkhineh) were tracked using a molecular method. The kinetics of bacteriocin-like substance production, as well as its stability (at high temperatures, different pH levels, and under different enzyme influences), were investigated. The antagonistic (well diffusion method) and anticancer (with MTT colorimetric technique) characteristics of enterocins generated by these isolates were also investigated in two human cancer cell lines. The results of the PCR test showed that isolates of Enterococcus faecium AUT-7KB and Enterococcus faecalis KUMS-T48 contained all three studied enterocin production genes, and the bacteriocin-like metabolites of these strains had strong antagonistic effects on Listeria monocytogenes and Bacillus cereus. These metabolites had high stability at different pH and became ineffective under the influence of protease enzymes (trypsin and pepsin), which indicated their protein nature. Additionally, metabolites of the KUMS-T48 isolate showed strong cytotoxic effects on two cancer cell lines, AGS and HT-29. According to the findings of the current research, enterocins of the E. faecalis KUMS-T48 strain are suggested as a suitable candidate for further anti-tumor studies, such as in vivo studies, after complete investigations of safety aspects.

Due to the widespread use of pesticides to protect agricultural products around the world and the accumulation of residues of these substances in plant tissue, most of the products that have been exposed to pesticides contain amounts of pesticide residues. The most popular and sensitive method for determining low amounts of pesticide residues in order to find out their maximum residue levels (MRLs) in food products is the chromatographic assay. In the present study, the diazinon, chlorpyrifos, imidacloprid, acetamiprid, thiacloprid and fenvalerate insecticides were extracted from cucumber samples by using QuEChERS method in combination with liquid-liquid microextraction and were determined by HPLC-DAD. For this purpose, the effective factors in the developed extraction method were optimized and the mentioned method was validated. Based on the results, the target analytes were successfully extracted simultaneously using 2 ml of a mixture of acetonitrile, methanol, and acetone (in the QuEChERS step). Further, the highest efficiency in the second extraction step was obtained using 65 µl of hexanol and 15% NaCl. The LOD between 0.36 and 0.57 ng/g, high repeatability in the range of 3.6 to 6.8 (based on the RSD%), and extraction recovery of analytes in the range of 76 to 84% of the developed method's merit figures indicate the method's high capability in extracting particular pesticides. Overall, the procedure described in this study is a simple and cheap method and has a good ability to extract the desired pesticides from cucumber samples.

Blue mold, caused by Penicillium expansum, is considered one of the most serious postharvest diseases of apple fruits. This study was conducted to evaluate the efficacy of thyme methanol extract to control the postharvest blue mold of apple fruit and its possible modes of action through on induction of biochemical defense mechanisms. In this study, the effect of thyme methanol extract was tested on spore germination and colony growth in vitro and peroxidase activity and total phenolic in fruit tissue were evaluated by calorimetric assay. The results showed the inhibitory activity of thyme extract on P. expansum. The extract with 8-20 µg/ml concentrations had 17-33% and 24-36% inhibition of spore germination and colony growth diameter, respectively. Thyme extract decreased blue mold area by 23.63-61.20% and the most effective extract was at 13.88 mg/ml concentration. The relationship between time and thyme extract concentration in relation to decay area was described by the quadratic model. Fruits treated with thyme extract had significantly higher phenolic content and peroxidase activity than the control fruits. The highest content of phenolic compounds and peroxidase activity were achieved in the 6th and 9th days after inoculation. The results of the induction of resistance in this study suggest that the natural products used have the potential for use in the integrated management of blue mold.

Phycobiliproteins (PBPs) are colored and water-soluble biliproteins that are found in cyanobacteria and rhodophytes. Based on their spectral characteristics, PBPs are divided into three types: Allophycocyanin, phycocyanin and phycoerythrin. PBPs, apart from their special function as sunlight-receiving antennas in the photosynthesis process, can be used as food dyes, nutrients, cosmetics, pharmaceutical industries and fluorescent probes in immunofluorescence analysis. Since PBPs have antioxidant, anti-tumor effects, as well as potential anti-inflammatory and anti-diabetic properties, in this review article, an attempt was made to investigate the properties and medicinal potential of PBPs along with their structural features. The results of the review of recent articles showed that the PBP part of proteins is very sensitive to environmental stress and this issue limits their use in the food industry. Therefore, it is necessary to use protective and coating materials to preserve the color. Consequently, they can prevent the denaturation of the protein structure, which not only increases the antioxidant properties but also increases the half-life of the food.

One of the products that is able to provide vitamins and amino acids needed for humans in the current conditions is edible button mushroom (Agaricus bisporus). Despite its properties, this food item can be the cause of many minerals and heavy metals due to its direct connection with the soil. The aim of this study was to investigate the amount of heavy metals and fungal acids in Campylobacter, Escherichia coli, Salmonella and Staphylococcus aureus in Isfahan city. In this study, 100 samples of edible button mushrooms were randomly selected from the supply centers of this product in Isfahan city and transported to the food hygiene laboratory of Shahrekord Azad University for chemical and microbiological tests. SPSS version 23 software and chi-square statistical analysis were used to analyze the data. According to the obtained results, out of 100 samples, 24 samples (24%) were infected with Campylobacter, 17 samples (17%) with Escherichia coli, 40 samples (40%) with Salmonella and 56 samples (56%) with Staphylococcus aureus. . Also, according to the results, the consumption of heavy metals, including lead, cadmium and arsenic, exceeded the standard. Based on the results obtained from the present study and pathogenic bacteria in mushrooms, it is necessary to be extremely careful in preparing edible mushrooms and refuse to eat them raw.