نشریه کیفیت و ماندگاری تولیدات کشاورزی و مواد غذایی
سال دوم شماره 3 (پیاپی 7، زمستان 1401)

Escherichia coli and Salmonella are gram-negative bacteria and are indicators of faecal contamination in food, and the presence of each of them in processed foods indicates lack of hygiene, and Staphylococcus aureus is a gram-negative bacteria. It is positive that it has the highest level of poisoning. The aim of the present study is to investigate the contamination with Staphylococcus aureus, Escherichia coli and Salmonella in cream sweets sold in Isfahan city and the antibiotic resistance of the obtained isolates. In this study, 120 cream sweets from the supply centers of this product in different parts of Isfahan city were randomly sampled and transferred to the specialized food hygiene laboratory of Shahrekord Azad University, next to the ice flask, in order to avoid secondary contamination. The standard method was used to search for microorganisms. The collected data was used in SPSS version 26 statistical software and chi-square test was used for data analysis. The results showed that Escherichia coli and Salmonella contamination was negative in all samples, but Staphylococcus aureus was confirmed in 4 cases of cream sweets. The samples were the most sensitive to tetracycline, streptomycin and amikacin and the most resistant to penicillin and ampicillin. In this survey, it was determined that a high percentage of the cream sweets offered in Isfahan city are in compliance with the existing standards in the society in terms of contamination and health quality to some extent, but in order to improve the health of the society,

Neem (Azadirachta indica) is known as a medicinal plant due to its antibacterial, antimalarial, antiviral and antifungal properties. The aim of this study is to investigate the antimicrobial activity of neem medicinal plant prepared with different solvents on antibiotic resistant Escherichia coli.Neem medicinal plant leaves were collected from Sistan and Baluchistan region, extracted in dry shade and using different solvents, and minimum inhibitory concentration and minimum lethal concentration were determined by microdilution method.The results of this study showed that the lowest inhibitory concentration of ethanol extract of neem against Escherichia coli was 2.5 mg/ml, and 2 strains were inhibited at this concentration, while the highest inhibitory concentration was 10 mg/ml and 4 strains were inhibited in this concentration.The lowest inhibitory concentration of neem acetone extract is 0.62 mg/ml, and one strain is inhibited at this concentration, and the highest inhibitory concentration is 5 mg/ml, and 5 strains are inhibited at this concentration. While the lowest and highest inhibitory concentrations against Escherichia coli were 1.25 and 10 mg/ml, and 1 and 3 strains were inhibited at this concentration.The lowest inhibitory concentration of neem acetone extract is 0.62 mg/ml, and one strain is inhibited at this concentration, and the highest inhibitory concentration is 5 mg/ml, and 5 strains are inhibited at this concentrationThe results showed that neem extract had a good inhibitory effect on Escherichia coli at low dilutions.

Today,the attention of researchers has been drawn to the use of natural preservatives instead of chemical compounds.In this empirical study, the effects of Boomadaran extract on the storage time and quality of frozen trout were examined. The studied treatments were the control treatment,mild soda salt treatment without extract couting, extract couting treatment without salt,soda salt treatment without extract couting . changes in pH in every treatment,during a period of 12 days of maintenance showed that,untile the sixth days of maintenance,no significant difference was observed in the experimental treatments.Yet,by the increase of time in the ninth and twelvth days the numerical quantity also increased. Moreover, the amount of proxide (pv)in the fish containing Boomadaran extract decreased after time.The level of Tiobarbiotic-acid index(TBA)increased during time of maintenance significantly in the sample compared with that of salt treatment and the extract so that this amount has increased to its highest level in the sample at the end of the maintenance period which showed a significant difference (p<0.05) compared with the fish sample including extract and salt. Also the amount of TVN in the sample under study has significantly risen during time in the sample treatment (p<0.05) . a significant difference was abserved from the sixth day, between the sample and the sample that mixed with Boomadaran extract(p<0.05). 1% Boomadaran extract had a significant effect on fish samples to keep their suitable quality and increase of storage.e.

Milk is a valuable food,that contains essential nutrients for the body,but this product is very perishable and has a short shelf life,so various adulterations may be done in it in order to more profit and increase the shelf life and also to covering the signs of spoilage.In this cross-sectional study,totally80samples(64samples of raw milk and16samples of pasteurized milk)were collected randomly from Birjand markets. All samples were tested in the food laboratory of South Khorasan provincial of standard and industrial research service for adulterations such as adding hydrogen peroxide,formalin, sodium hypochlorite,sodium bicarbonate,salt, starch and water to milk and removing the milk fat.Results of this study showed that water was not added to any of raw and pasteurized milk samples.The mean of fat and salt in raw milk samples was significantly higher and lower than the standard limits,respectively(P<0.001).Salt was not found in pasteurized samples. The mean of milk acidity after boiling,compared with before boiling, both in raw and pasteurized milk decreased significantly(P<0.05), but this decline was less than 1˚dornic.The mean of fat and salt in raw milk samples was significantly higher than pasteurized milk samples(P<0.001)but in terms of acidity before and after boiling,significant difference was not observed in raw and pasteurized milk samples(P>0.05).In terms of hydrogen peroxide,formalin,sodium hypochlorite and starch,any adulterations were not found in this study. Fortunately,the results of this research showed that in all samples of raw and pasteurized milk which collected from Birjand none of above mentioned adulterations was done and in this respect all samples were in appropriate conditions

In the present study, the effect of carboxymethyl cellulose oral active coating containing salvia officinalis extract on the quality and shelf life of common carp fillet during the storage period in the refrigerator (4±1℃) was investigated. Common carp fillets in five control groups were treated with carboxymethyl cellulose coating without extract and containing 0.5% and 1% sage extract and kept in refrigerator for 12 days, chemical (pH, TVN, PV, TBA) and microbial (Total and Psychrophilic bacterial load) indicators were investigated. The results of this research confirm the better performance of carboxymethyl cellulose coating containing 1% sage extract compared to other treatments; So that the chemical indices and amounts of total and Psychrophilic bacteria as microbial indices of quality control of had better results than other treatments until the end of the storage period and showed was able to provide acceptable quality by reducing the Total bacterial amount and the amount of Psychrophilic bacteria in the samples. According to the results of the evaluation chemical indicators affecting spoilage, the application of carboxymethyl cellulose coating containing 1% of sage extract can more effectively cause damage by controlling and reducing the oxidation of lipids than other treatments. Maintain the quality of common carp fillets during the storage period. Therefore, Salvia officinalis extract, having antioxidant and antimicrobial properties, as a natural biological preservative in combination with coating of carboxymethyl cellulose, can be used as a method to maintain the quality and increase the shelf life of common carp fillets during storage in the refrigerator.

The purpose of this study was to evaluate the effect of various edible oils (soybean, sunflower and canola) at %30 weight using a separate and combination of oils in seven samples on the quality and oxidative degradtaion of low-fat mayonnaise during a pediod of 6 months at a temperature of 10 degree Celicus under controlled conditions. the results showed that the pH and acidity of all samples were in the range of 3.04-3.16% and 0.932-1.019%, respectively. During the maintenance period, the pH and viscosity of the mayonnaise samples decreased gradually, while acidity increased. The samples containing %15 sunflower (A5) and the equal mixture of oils (A3) of %10 each, had the highest viscosity. All samples had a perfect emulsion stability during maintenance. Combination of different oils influnced the oxidation indices of low-fat mayonnaise significantly so that the lowest oxidation index was related to the sample containing %15 canola oil (A6). Throughoput the time, the amount of peroxide, anisidine and totox of all studied samples decreased sifnificantly. the results of sensory evaluation showed that oil type did not have a significant effect on taste, texture, sense of mouth, smell and general acceptance of low-fat mayonnaise. The lowest taste rate was for the sample containing %30 canola oil or all canola(A2), followed by a %15 canola oil sample (A6). However, all the mayonnaise samples were acceptable in terms of sensory characteristics. finaaly, according to the obtained results, the sample of %15 canola oil (A6) was considered as an optimal sample.

To optimize the chitosan film with level, molecular weight and solvent and then use it in the composite coating in the appropriate mixing ratio, in a completely random design using the 23 factorial methods with 3 factors, level (2 and 4 %), molecular weight (high and low) and solvent (acetic acid and citric acid), was carried out to investigate the physical and mechanical properties of chitosan film. Then the selected film was incorporated in the chitosan-polyvinyl alcohol composite coating, aiming of achieving the optimal mixing ratio and affecting the internal quality parameters of eggs, in a completely randomized design with 6 treatments including uncoated eggs (control), coated with a pure coating of chitosan and polyvinyl alcohol separately as well as composite coatings of chitosan: polyvinyl alcohol (25, 50 and 75% of each component). The results showed the highest tensile strength and Young's modulus (0.16 and 2.45 MPa, respectively) and water vapour impermeability (2.17.10-8 g/msPa) in 4% chitosan film with high molecular weight dissolved in acetic acid and the highest elongation at break (54.33%) was observed in chitosan film in citric acid (P<0.05). Also, eggs coated with chitosan-polyvinyl alcohol at 25:75 have the lowest weight loss (0.57%) and the highest values of Haugh unit (61.00) and yolk index (0.37) (P<0.05). Therefore, it is possible to use chitosan-polyvinyl alcohol composite coating in the optimal mixing ratio (25% chitosan: 75% polyvinyl alcohol) as a packaging material to extend the shelf life of eggs for at least 2 weeks at ambient temperature.