The aim of this study was to investigate the impacts of NaCl, bile salts, and their combinations on the viability of Lactobacillus casei in probiotic yogurt. For this purpose, the antibacterial activity of NaCl and bile salts was investigated via the microdilution technique by determining the minimum inhibitory concentration (MIC) against L. casei. Further, the stress effects of 50% MIC on NaCl and bile salts on the L. casei were examined by comparing the stress treatments with the control in terms of the L. casei population, pH, acidity, and syneresis percentage in probiotic yogurt during storage in the refrigerator for 28 days. According to the results, the L. casei population and pH decreased in all the treatments during the storage time, such that the intensity of the decrease in the control treatment was lesser than in other stress treatments (p<0.05). The acidity and percentage of syneresis during the storage time increased for all the treatments, with the increase being less in control than in the other stress treatments (p<0.05). The control scored the highest in the sensory evaluation (p<0.05). In conclusion, applying stresses below the MIC had a negative effect on the survival of L. casei in the probiotic yogurt until the end of 28 days and the outcome was not as expected. پرونده مقاله

Biodegradable active packaging containing essential oils with antimicrobial properties is one alternative strategy that can be considered by the food packing industry to reduce the use of environmentally harmful synthetic polymers. Chitosan is a safe, natural, no allergen, and biocompatible polymer with health benefits. This study was conducted to investigate the effects of chitosan coating contain Ajwain essential oil (AEO) on the shelf-life of chicken breast meat during refrigerated storage. AEO was extracted and its composition was analyzed by GC/MS, the AEO was added to chitosan solution in different concentrations (0, 0.5%, and 1% (v/v)) and chicken breast meat was coated by chitosan solution, The microbiological properties of chicken breast meats, such Total aerobic mesophilic bacteria (AMB), Enterobacteriaceae, total aerobic psychrotrophic bacteria (APB), and Pseudomonas spp. were determined during 13 days of storage. The results showed that using of AEO has significant effects on the reduction of all followed groups of microorganisms compared with the control group. In the present study, 1% v/v AEO treatment was the most effective in microbial groups throughout the storage period. This study showed that chitosan coating contains 1% AEO have good antimicrobial activity and can be used to extend the shelf-life of the meat products. پرونده مقاله

The use of films with natural origins and natural antimicrobial agents has become one of the novel methods of food packaging. In this study, the antibacterial activity of active films against two microorganisms, Staphylococcus aureus (ATCC 65138) and Escherichia coli O157: H7 (ATCC 25922) were evaluated by disk diffusion method. Also, the antimicrobial properties of gelatin film containing different concentrations of Pimpinella anisum essential oil (0, 0.3, and 0.6 and 0.9%) were studied on minced beef at refrigerator temperature. The treatments were stored for 8 days after packaging and the microbial (total count of aerobic bacteria, psychrophilic bacteria, Pseudomonas spp., Enterobacteriaceae and mold/yeast), chemical (TVB-N and peroxide value) and sensory (color, odor, and taste) properties were examined. The main components of the essential oil were trans-anethole (87.39%), (Carvone8.79%), and Hexadecanoic (2.26%), Heptadecane1.56%). Results showed that all microbial and chemical properties related to treatments containing antimicrobial agents were significantly (p<0.05) less than the control treatment. Considering the acceptable microbial limit for minced beef at refrigerator temperature, the shelf-life of treatments wrapped with films containing essential oils increased by at least 3 days without any adverse without any unfavorable organoleptic properties. پرونده مقاله

Antimicrobial packaging is an innovative active packaging, especially for meat and meat products. The present study has been carried out with the objective of prolonging the shelf life of chicken meat by using gelatin-chitosan (GC) film containing different concentrations of Cinnamon zeylanicum essential oil (CZEO) (0, 0.3, 0.6, and 0.9% v/v) at the refrigerated condition for 12 days. The obtained results indicated that the microbial count of samples wrapped with the films incorporated with the CZEO was significantly lower than control and remained below the acceptable limit of meat (7 log CFU/g). The total volatile base nitrogen (TVB-N) was 7.11 mg/100 g and after 6 days reached 30.18 mg/100 g in control, whereas it was lower than 25 mg/100 g for samples wrapped with GC films containing 0.6% and 0.9% CZEO. Compared with the control sample, the levels of peroxide value (POV) of the wrapped samples with GC films incorporated CZEO at 0.3%, 0.6 and 0.9% were decreased by 2.07, 3.23, and 3.4 meq peroxide oxygen/1000 g lipid, respectively, at the end of storage time. As a result, the integration of CZEO into GC film can extend the shelf life of the chicken meat in refrigerated conditions for at least 12 days without any unfavorable organoleptic properties پرونده مقاله

The aim of this study was to investigate the physicochemical properties and survival of Lactobacillus rhamnosus LGG in synbiotic wet Doineh, a traditional Iranian fermented food enriched with different ratios of inulin. Milk and wheat bulgur were cooked in the conventional method and then mixed with LGG strain and different ratios of inulin (0, 2.5, 5, 7.5, and 10 percent). After 24 h of fermentation at 37ºC, the samples were stored at 4ºC for 21 days. pH, acidity, sensory evaluation, and probiotic culture were measured at 24 h after fermentation and on days 7, 14, and 21, using a pH meter, potentiometric, 5-point hedonic scale, and pour-plate methods, respectively. Protein, fat, solids content, and ash were determined by Kjeldahl, Soxhlet, dry weight at 100105°C and 550ºC oven methods after 24 h of fermentation. The samples containing inulin showed significantly slower changes in pH and acidity. The viability and survival of LGG increased in the samples with higher amounts of inulin due to its prebiotic effect, and these changes were significant. The 2.5%, 5% and 7.5% inulin models had more acceptable sensory characteristics. Traditional foods and their preparation methods are suitable targets for developing health-oriented products, and functional foods with nutraceutical capabilities can be designed and produced based on them. پرونده مقاله

This study investigated the impact of Bacillus coagulans, potassium chloride, and yeast extract on probiotic vegetable sausages' microbial, physicochemical, and sensory properties with reduced salt content during refrigerated storage. The sausages supplemented with potassium chloride solution and 1% or 2% yeast extract showed an initial viable count of B. coagulans at 8.34 log CFU/g, which decreased to 7.2 and 7.42 log CFU/g after four weeks of storage. The addition of potassium chloride and yeast extract improved the viability of B. coagulans by approximately 0.2 log CFU/g compared to sausages without the mixture. Moreover, including these ingredients led to a gradual decrease in pH over the storage period. Sensory evaluation indicated that adding potassium chloride and yeast extract enhanced taste scores and overall acceptance but negatively impacted color characteristics. These findings demonstrate that substituting salt with potassium chloride and incorporating yeast extract enhances the survival of probiotic B. coagulans, lowers pH during refrigerated storage, and improves sensory attributes in vegetable sausages. The study suggests that combining potassium chloride, yeast extract, and probiotic bacteria in plant-based meat products like sausages offers a scientific and effective approach to promoting healthier consumption patterns. However, it emphasizes the importance of carefully determining the appropriate concentration of these ingredients based on the sensory evaluation results. پرونده مقاله

Foodborne diseases are considered as one of the main problems of public health. Escherichia coli O157H7 are responsible for major outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) throughout the world. The mortality is originated from the production of a Shiga toxin (Stx) by these bacteria. Garlic essential oil (GEO) has antibacterial effects on many food-borne pathogens. Therefore, this study was aimed to evaluate the antibacterial activity of the Allium sativum L. EO and its nanoliposomal form on the virulence of E. coli O157:H7. Reverse passive latex agglutination test was used to detect Shiga toxin2 (Stx2) production after exposure to sub-inhibitory concentrations of free and nanoencapsulated EO. Also, the effect of sub-inhibitory concentrations of free and nanoliposomal form of GEO was evaluated on Stx2 gene expression and the relative transcriptional level of Stx2 gene was determined by real-time PCR. It was found that the sub-inhibitory concentrations of liposomal form of EO (50 and 75%) had a significantly higher inhibitory effect on Stx2 titer than its free form (p<0.05). Also, increasing the concentration of EO and nanoencapsulated EO significantly reduced Shiga toxin 2 gene expression according to control. Using 75% sub-inhibitory value of free and nanoliposome GEO, the relative transcriptional level of Stx2A gene was reduced from 0.938 to 0.667 and 0.931 to 0.659, respectively. Based on our findings, different methods of nanoencapsulation should future study to improve nanoliposome efficacy to suppress toxin production on expression level. پرونده مقاله

There has been a growing increase in the consumption of Ready To Eat (RTE) vegetables among people owing to the health benefits of a diet rich in vegetables, because of hectic life styles, the use of Ready To Eat vegetables has gained popularity in recent years. RTE vegetables are subject to minimal processing and are consumed without being heat treated, they may, thus, contain human food borne pathogens. Listeria monocytogenes is one of the pathogens that has been widely reported in different outbreaks associated with the consumption of RTE vegetables. In this study the growth potential of L. monocytogenes in different types of RTE pre-cut vegetables stored at reasonably foreseen temperatures in the distribution chain of fresh produce was evaluated. Total aerobic microorganisms, lactic acid bacteria, pH and Aw were measured to characterise the vegetables. The results showed that some of the tested products (grapes, tomato, white cabbage and red cabbage) had a growth potential (δ) higher than 0.5 Log10 (CFU/g) during their shelf life and can therefore, support the growth of Listeria monocytogenes. By way of conclusion, conducting different challenge tests in the factories producing these convivence products seems of great importance. پرونده مقاله

یکی از چالش‌های اصلی در استفاده از پروبیوتیک‌ها زنده و فعال نگه‌داشتن آن‌ها در حین فرآیند تولید و نگهداری مواد غذایی است. از این رو مطالعه حاضر با هدف بررسی اثر استرس‌ کمتر از حداقل غلظت بازدارندگی بر زنده‌مانی لاکتوباسیلوس کازئی و برخی از خصوصیات فیزیکوشیمیایی ماست پروبیوتیک در طی دوره نگهداری در یخچال انجام شد. اسانس گیاه زیره سبز به روش تقطیر با بخار آب استخراج و ترکیب آن با دستگاه گاز کروماتوگرافی طیف سنج جرمی GC/MS تعیین شد. سپس اثر استرس اسانس زیره سبز به میزان 50 درصد MIC، به‌عنوان تیمار استرس در مقایسه با شاهد روی جمعیت باکتری‌های لاکتوباسیلوس کازئی، pH، اسیدیته و درصد آب‌اندازی در ماست‌های پروبیوتیک طی 28 روز نگهداری در یخچال مورد ارزیابی قرار گرفت. تجزیه و تحلیل داده‌ها به روش آنالیز واریانس Tukey در نر‌م‌افزار SPSS نسخه 18 صورت گرفت. مطابق نتایج مربوط به ترکیبات تشکیل دهنده اسانس، بیشترین ترکیب را پروپانال- 2متیل-3- فنیل با 2/24 درصد تشکیل داده بود. همچنین نتایج مربوط به ماست نشان داد، تعداد باکتری لاکتوباسیلوس کازئی و pH در هر دو تیمار طی دوره نگهداری کاهش یافته بود به‌طوری که شدت کاهش pH در تیمار تحت استرس در مقایسه با تیمار شاهد بیشتر بود (05/0P <). اما تغییرات باکتری لاکتوباسیلوس کازئی در دو تیمار اختلاف معنی داری باهم نداشتند (05/0P >). مقدار اسیدیته و درصد آب‌اندازی طی دوره نگهداری برای هر دو تیمار افزایش یافته بود و شدت افزایش در تیمار تحت استرس بیشتر از شاهد بود (05/0> .(P در مجموع نتایج مطالعه حاضر نشان داد اعمال استرس‌های کمتر از حداقل غلظت بازدارندگی باعث زنده‌مانی باکتری لاکتوباسیلوس کازئی به مقدار توصیه شده ( CFU/ ml107 -106) در ماست پروبیوتیک تا پایان دوره نگهداری شده بود. پرونده مقاله