JOURNAL OF FOOD HYGIENE
Year:2016 | Volume:6 | Issue:2 (22)|Papers Count:9

The application of natural compounds including green tea extract (GTE) in food preparation and pharmaceutical industries is limited. Encapsulation in nanoliposomes could be used as a delivery system to protect these compounds during processing and storage. In this study physicochemical characterization, total phenol content and antibacterial and antioxidant activity of green tea extract encapsulated in nanoliposomes were evaluated. GTE was encapsulated in liposomes by thin film layer method and reached to nanoscale with sonication. The antioxidant activity of nanoliposomal GTE was estimated by DPPH assay. The antibacterial activity of nanoliposomal GTE against Bacillus cereus (ATCC11778), Salmonella typhimurium 138 phage type 2, Escherichia coli O157: H7 and Listeria monocytogenes (ATCC19118) was determined using well diffusion technique. The mean diameter of nanoliposomes was about 44.7±1.9 nm and had 0.203±0.014 polydispersity index. Entrapment efficiency of nanoliposomal GTE under the optimum conditions was 97%. Antibacterial activity of GTE was significantly increased after encapsulation in nanoliposomes. The strongest antibacterial activity of nanoliposomal GTE was seen against L. monocytogenes with an inhibition zone of 16.2 mm while E. coli was the most resistance strain with an inhibition zone of 14 mm. Furthermore, the antioxidant activity of GTE was significantly increased after nanoliposome encapsulation since the IC50 value of nanoliposomal GTE was decreased to 1.78 mg/ml. Nanoencapsulation effectively enhanced beneficial properties of GTE including antimicrobial and antioxidant activities.

Scrophularia khorassanica belongs to the Scrophulariaceae family that geographically grows wild only in Iran-Khorasan. There is insufficient information about its composition and antibacterial activity. Due to the application of S. khorassanica and related species in traditional medicine, the aim of this study was to determine antimicrobial effect of S. khorassanica aqueous and methanolic extracts on the growth of Escherichia coli and Staphylococcus aureus and also to determine the composition of the essential oil in-vitro. Extracts and the essential oil were prepared respectively by maceration and hydro-distillation methods. The composition of the essential oil examined by GC/MS and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determined by broth micro-dilution assay. Composition analysis identified a total of 28 various components in which the main components were 1, 3-Bis (trimethylsilyl), benzene (34.93%), р-Cymene (12.55%), Palmitic acid (6.79), Thymol (6.22%), Linalool (4.59%), 2-undecanone (4.35%), Sorbitol (1.87%), Carvacrol (1.74%), g-Terpinene (1.06%), b -Elemene (1.03%) and a-Pinene (0.3%). The MIC for methanolic extract against E. coli and S. aureus was 12.5 and 25 mg/ml, respectively. In the case of aqueous extract, it was estimated at 6.25 and 12.5 mg/ml, respectively. Based on these results, the aqueous extract had the strongest antibacterial effect. It was concluded that Scrophularia khorassanica extract can be used as an natural preservative.

Cadmium is a wide-spread heavy metal that causes a wide range of health problems in animals and humans. Many reports showed the biosorption of heavy metals by bacteria. The objectives of this study were to evaluate the potency of probiotics bacteria of Lactobacillus plantarum and Bacillus coagulans against cadmium adsorption in rats. Twenty four male adult Wistar rats were randomly divided into six groups. Cadmium treated groups received 1 ml of 100 mg/ml CdCl2 and probiotics groups were administrated 1 ml of (109 CFU/ml) of probiotics during 24 days by special gavage needle once daily. Levels of cadmium were determined by using graphite furnace atomic absorption spectrometry. Probiotics B. coagulans and L. plantarum caused 29.8% and 19.3% increasing in removal of cadmium through defecation and decreased 10.9 and 21.5 % of cadmium accumulation in kidney of Wistar rats. The results showed that oral administration of both probiotics offered a significant protective effect against cadmium adsorption in rats.

The present study was aimed to investigate the antibacterial activities of the Laurus nobilis, Peganum harmala and rosemary extracts against Staphylococcus aureus and Escherichia coli. Thus, the ultrasonic extracts were performed using the aqueous, ethanol, hydro-alcoholic or chloroform phases. The microdilution technique was used to evaluate the antibacterial activities which was finally reported as the MIC and MBC values. All the extracts showed the antibacterial activities against the bacteria at the concentration of 6.25%. However, the metalonic extract exert a maximum antibacterial activity. The extract of three plants revealed the same antibacterial activity against E. coli, but the ethanoloic extract from P. harmala showed a maximum antibacterial activity against S. aureus at the concentration of 6.25%. Results of the current study showed the similar antibacterial activities of the extracts against E. coli, meanwhile, the maximum antibacterial effect on S. aureus was observed by applying alcohol or water as a solvent. In general, this paper proposed that ultrasound assisted extraction was quick and cost effective approach to extract the plants. In addition, ethanolic solvent was found as the best selection among the aqueous, hydro-alcoholic or chloroform solvents.

Heavy metals are the most important chemical pollutants of foods. Milk and dairy products due to the nutritional functions are largely consumed by infants and children around the world. The purpose of this study was to analyze Zn, Pb, Cd and Cu contents in raw cow milks produced in dairies of Lorestan industrial livestock zone during 2014. A total of 24 milk samples was collected from eight dairies. The samples were subjected to acid digestion according to standard method. Afterwards, the metal contents were determined using ICP-OES. All statistical analyses were performed using the SPSS statistical package. The results showed that mean concentrations of Zn, Pb, Cd and Cu in milk samples were 3072±674, 2720±2790, 104±18.5 and 142±149 mg/kg, respectively. Also comparison of the mean concentrations of the metals with the WHO maximum permissible limits in milk revealed that the mean concentrations of all metals were significantly higher than permissible limits. Because of the mean concentrations of Zn, Pb, Cd and Cu in milk samples were higher than Mean Residual Limits, therefore to achieve the consumers’ safety, monitoring of feed intake, water supplies, soil properties around livestock and forage crops and control of pollutants emission from industries near the livestock are recommended.

The aim of study was to produce a low-fat cacao containing probiotic yogurt. For this reason a combination of probiotic bacteria, lactobacillus acidophilus and Bifidobacterium lactis (3% w/w) together with 0.8% cacao powder, 5% sugar as a well as 1.2% cacao powder with 7% sugar were used to produce a synbiotic yogurt (0.5% and 1.5% fat). Populations of probiotics bacteria, physiochemical and sensory properties of the yogurt samples were evaluated throughout the storage period (1, 7, 14, and 21 days). Result showed that cacao as prebiotic could significantly increase the viability of L. acidophilus (P<0.01), besides no significant difference was observed between the populations of B. lactis in the chocolate yogurt and control samples. The highest quantity of the probiotic bacteria was observed at day 7, followed by a decrease in their number, however their populations remained above 7 log cfu/g. Moreover, pH value of the samples decreased over the time of storage, but pH value of the cacao-containing samples increased significantly (P<0.01). In comparison with the control group, no significant increase was recorded in the lipid content of the samples with cacao and sugar, meanwhile the amount of dry matter was higher than control samples (P<0.01). It could be concluded that apart from the prebiotic properties of cacao on L. acidophilus, it can improve the nutritional value of probiotic yogurt and increases the calorie of the product. However for achieving better sensory properties, changes should be considered in the formulation.

Fish and other marine products are valuable source of protein for human. This research was conducted to determine histamine concentration in fresh and canned muscles (White and dark) of Katsuwonus pelamis.For this purpose 9 samples ofKatsuwonus pelamis and 15 samples of canned fish were prepared. After biometric evaluations, dark and light muscles were separated. Histamine content was measured with Thin Layer Chromatography method. The results showed that the average content of histamine in dark and white muscles were 154.3±52.46 and 124.4±47.05 mg/g, respectively. Moreover, the average concentration of histamine in canned was 160.52±87.59 mg/g. Although the histamine concentration between white muscle and canned fish was statistically significant, results revealed no significant difference between dark muscles with canned samples. Histamine cconcentration in all samples was lower than FDA standard (20 mg/100g), thereforeKatsuwonus pelamis and canned fish would not cause allergic reactions in the consumers.

Due to the ever-increasing of antibiotic-resistance microorganisms and the tendency towards the application of natural preservatives, in the present study the ethanolic extract of stalk portion of KurdistanGundelia tournefertti L. was extracted in rotary evaporator. The antibacterial effect (MIC and MBC) of the extract was investigated against Staphylococcus aureus and Escherichia coli.using agar dilution assay on Muller-Hinton agar. The experiment was conducted with 3 replicates and probity analysis of the data was analyzed using SAS 9.2 software. Result showed that both MIC and MBC for S. aureus was 62.5 mg/ml. Moreover, the MBC and MIC values for E. coliwere estimated at 31.25 mg/ml and 15.62 mg/ml, respectively. Since ethanolic extract of G. tourneferttiwas highly effective on indicator bacteria, it can be used in combination with the other preservatives to protect foods from foodborne organisms.