JOURNAL OF APPLIED MICROBIOLOGY IN FOOD INDUSTRY
Year:2024 | Volume:10 | Issue:4|Papers Count:9

This article examines the methods of measuring antibiotics in food samples. Antibiotics are of particular importance as one of the important factors in maintaining the general health of society. In this article, different methods of measuring antibiotics in food samples, including chromatography methods, spectroscopic methods, and standard immunoassay methods, are examined. The purpose of this article is to present a comprehensive and complete review of the available methods for measuring antibiotics in food samples so that people with the right to access scientific information can benefit from the latest achievements in this field. Emphasizing standard and accurate methods, this article introduces effective and reliable methods for measuring antibiotics in food samples, and as a result, it can help improve the quality and credibility of future research in this field.

The Lactobacillus delbrueckii subsp. bulgaricus is one of the most well-known probiotic lactic acid bacteria, which is traditionally used in fermented products, especially dairy products. Few studies have focused on the optimization of L. delbrueckii subsp. bulgaricus biomass production. Therefore, it is necessary to use the design of the experiment and response surface methodology in the optimization of this important probiotic strain. The L. delbrueckii subsp. bulgaricus strain isolated from fermented products of Tehran province was used in this study. By studying one-factor-at-a-time, carbon and nitrogen sources were evaluated. Three factors of glucose, yeast extract and peptone were confirmed to be evaluated in the optimization test. Then, using the experimental design and response surface methodology, the Box-Behnken model was used to optimize these three variables. The results obtained from Box-Behnken design with statistical software identified the full quadratic model for significant optimization. This model suggests that in the concentration of glucose 20 gr/L and the concentration of yeast extract 25 gr/L and peptone 30 gr/L, a dry weight of 2.132 gr/L is obtained, which was confirmed. This study has been successful in optimizing carbon and nitrogen sources on L. delbrueckii subsp. bulgaricus biomass production. The variables and values obtained are confirmed by other studies, but finally, due to the restricted studies that have been done on the optimization of the cultivation conditions of this probiotic strain, more investigations are suggested to confirm the findings of this study.

In this study, the effects of Nano chitosan and chitosan coating on extending the shelf life of beef hamburgers during storage in a refrigerator (at a temperature 4±1°C) over a period of 24 days were evaluated. For this purpose, hamburgers were assessed in five treatments, including chitosan solutions with concentrations of 1%, 2%, Nano-chitosan 1%, Nano-chitosan 2% and distilled water solution as a control sample on days 0, 3, 6, 9, 12, 15, 18, 21 and 24. The antimicrobial effect of the coating was evaluated by counting the total viable count (TVC), psychrotrophic bacteria, lactic acid bacteria, molds and yeasts. Additionally, chemical properties were assessed by measuring pH, peroxide value (PV), Thiobarbituric acid (TBA), and total volatile basic nitrogen (TVB-N). Sensory evaluation, which included the assessment of taste, odor, color, and overall acceptance was conducted by five trained evaluators. The results of the study showed that both chitosan and Nano-chitosan coating were effective on hamburger samples stored at refrigerator temperature. However, samples with Nano-chitosan coating had significantly greater antimicrobial effects compared to those with chitosan coating and were better able to control oxidation during the storage period. These results indicate the greater efficiency of chitosan at the nanoscale compared to larger-sized chitosan. In this study, the treatment with 2% Nano-chitosan solution showed the best preservation results.

Endometriosis, a common disease in women, ranks second only to all types of cancer. It significantly impacts women's overall health and reproductive health, with statistics indicating that one in every 10 women worldwide battles this condition. Endometriosis has various causes, including retrograde menstruation, immune system disorders, hormonal imbalances, surgical complications, and genetic factors. Traditional treatments for endometriosis have included non-steroidal anti-inflammatory drugs (NSAIDs), hormone therapy, and surgery, each with varying success rates and effectiveness. Recently, there has been discussion about the potential role of probiotics and estrobolome in addressing endometriosis through the estrogen-gut microbiota axis. An imbalance in gut microbiota can lead to an increase in beta-glucuronidase, which hinders the binding of estrogen and glucuronic acid, resulting in elevated circulating estrogen levels through enterohepatic circulation. This significantly contributes to the growth of abnormal lesions in endometriosis. Consequently, patients with endometriosis have a higher number of beta-glucuronidase-producing bacteria in their gut microbiota. Furthermore, research indicates that probiotics not only have the potential to inhibit the progression of endometriosis but are also effective in alleviating associated pain.

The use of probiotics due to their numerous benefits in food depends on their survival during heat processing. Therefore, their capsulation with heat-resistant carriers is considered a useful technique. Marmalade, as an attractive and popular food item for breakfast or snakes, has a high potential for enrichment with probiotic microcapsules. In this research, sodium alginate, whey powder concentrate and Persian gum were used as heat-resistant carriers for lactobacillus plantarum encapsulation, and the best formula based on the efficiency of live probiotics was added to carrot marmalade with Brix 70 and packaged by thermoforming method. After packing the marmalade, the survival rate of probiotics during storage and its survival rate in the simulated environment of the stomach and intestines were investigated along with a textural test and organoleptic test to evaluate it as a functional food. The results showed that the number of active probiotics in marmalade after 60 days of storage reached about 0.91×106 (5.95 logarithm of colony units). Also, with the selected formulation, the survival of probiotics in the simulated environment of the stomach and intestines decreased by only 2 logarithmic cycles during 120 hours, which was about 6 logarithmic cycles in free cells. Examining the texture of carrot marmalade in terms of firmness and consistency until the final day of storage also indicated an increase in the mentioned factors. In the sensory evaluation, although the panelists did not see a difference between mouthfeel and color, they considered a higher score for smell and taste in the control sample

threonine amino acid is one of the essential amino acids for livestock and poultry, therefore its use as a food supplement is of particular importance in nutrition. Today, one of the common methods of threonine production is the use of microorganisms, especially Corynebacterium glutamicum. Fast production, easy cultivation and low production cost are the advantages of using this bacterium to produce threonine amino acid. In this study, c.glutamicum (ATCC13032) was cultured in the standard culture medium called ISP-2, and then to optimize the ISP-2 culture medium, the effect of additives such as cheese water, bagasse, molasses, and corn syrup on threonine production tested Threonine production rate was evaluated using chromatography method. After reviewing the results, the best physical and chemical conditions for threonine production were selected and the expression levels of key genes involved in threonine production, including thrB and thrC, were analyzed by Real-time PCR technique. The results obtained from chromatography showed that the concentration of 0.4 grams per liter of cheese water provides the best conditions for the production of threonine. So that the concentration of threonine produced increased by 33271.53 mg/L in the cheese water sample. Based on Real-time PCR results, cheese water culture medium increased thrB gene expression by 2 times and thrC expression by 1.08 times. Based on the obtained results, physicochemical changes in the culture medium can have a significant effect on threonine production by Corynebacterium glutamicum bacteria.

In order to investigate the antifungal effects of essential oils of some medicinal plants, including rosemary, which is often consumed as an edible vegetable, a comparative study of the fungicidal effects of rosemary essential oil under the influence of different fertilizers on Fusarium fungus was designed and implemented. In the first part, the experiment was conducted in a randomized complete block design with four treatments and three replications, in which the fertilizer treatments were control, nitrogen fertilizer from urea source, organic animal manure (cow), and vermicompost, after planting and passing the period. At the end of the operation, the plants were harvested and their essential oils were measured using conventional and recommended scientific methods. According to the results obtained, the most essential oil was from the use of chemical nitrogen fertilizer from urea fertilizer source, and the lowest amount of essential oil was from the control treatment (no fertilizer use). In the second stage, the experiment was conducted by planting spores of the Fusarium fungus in the designed culture medium, while confirming the antifungal effects of the essential oil of the medicinal plant rosemary. It led to the conclusion that the essential oils produced from the use of chemical fertilizers and vermicompost showed more and better inhibitory effects than other essential oils.

The measurement of antibiotics is of great importance. Therefore, in this research, a colorimetric sensor based on the reaction of ferric iron and norfloxacin and the formation of a black complex resulting from their reaction has been designed. For this purpose, all conditions were optimized using a one-factor-at-a-time method to achieve the highest sensitivity. Then, under optimal conditions (pH=3.0, contact time 60 seconds, iron concentration 100 ppm), the designed sensor showed a suitable linear range from 1 to 100 micromolar. The detection limit and quantification limit are 0.31 and 0.99, respectively. In the developed method, a smartphone and the analysis of green, red, and blue colors from the captured images were used as the analytical signal, thus the developed method also benefits from portability and low cost. Finally, the proposed method was used for the analysis of norfloxacin in three wastewater samples, and the results were compared with a standard method.

In the natural environment, exopolysaccharides are a common feature of microbial biofilms and play a key protective and structural role, being among the first participants in the synthesis of exopolysaccharides that form the extracellular polymeric matrix and cause the formation of microbial aggregations with varying levels of complexity called biofilms. Cyanobacteria are among the first organisms to establish themselves in environments with less favorable conditions, such as desert soils and rocky and uncovered substrates, and by synthesizing exopolysaccharides, they create a hydrated microenvironment with structural strength as well as chemical/physical protection against living and non-living stressors, leading to the formation of biofilms. However, despite the important role of cyanobacterial exopolysaccharides, many aspects of their role and their relationship with biotic and abiotic factors are still unclear. Therefore, this review article examines their role in protecting the microbial community by searching for the latest articles.