Advantages and disadvantages of the use of irradiation for food preservation

Food irradiation is a physical method of processing food (e.g. freezing, canning). It has been thoroughly researched over the last four decades and is recognized as a safe and wholesome method. It has the potential both of disinfesting dried food to reduce storage losses and disinfesting fruits and vegetables to meet quarantine requirements for export trade. Low doses of irradiation inhibit spoilage losses due to sprouting of root and tuber crops. Food- borne diseases due to contamination by pathogenic microorganisms and parasites of meat, poultry, fish, fishery products and spices are on the increase. Irradiation of these solid foods can decontaminate them of pathogenic organisms and thus provide safe food to the consumer. Irradiation can successfully replace the fumigation treatment of cocoa beans and coffee beans and disinfest dried fish, dates, dried fruits, etc. One of the most important advantages of food irradiation processing is that it is a coldprocess which does not significantly alter physico-chemical characters of the treated product. It can be applied to food after its final packaging. Similar to other physical processes of food processing, (e.g. canning, freezing), irradiation is a capital intensive process. Thus, adequate product volume must be made available in order to maximize the use of the facility and minimize the unit cost of treatment. Lack of harmonization of regulations among the countries which have approved irradiated foods hampers the introduction of this technique for international trade. Action at the international level has to be taken in order to remedy this situation. One of the important limitations of food irradiation processing is its slow acceptance by consumers, due inter alia to a perceived association with radioactivity. The food industry tends to be reluctant to use the technology in view of uncertainties regarding consumer acceptance of treated foods. Several market testing and consumer acceptance studies have been carried out on food irradiation in recent years. These studies showed that, if the safety and the benefits of food irradiation were properly explained, the consumers were willing to accept irradiated foods. Considering its potential role in the reduction of post-harvest losses, providing safe supply of food and overcoming quarantine barriers, food irradiation has received wider government approvals during the last decade. There is also a trend towards increased commercialization of irradiated food. Currently, there are 47 irradiation facilities in some 23 countries being used for treating foods for commercial purposes.     

Pb in medicinal plants from Jordan

This is the first report on Pb in medicinal herbs from Jordan. Medicinal herbs may present a health risk due to the presence of toxic metals. Seventy-nine dry medicinal plant samples were collected from herbalist shops in Jordan. The plants were digested with acids and analyzed for total Pb concentration using atomic absorption spectrometry. Mean Pb concentration was 15.9 μg/g on a dry weight basis. Our results show that Pb concentrations in Jordan medicinal plants are higher than published data in other countries. The highest level of 33.4 μg Pb/g was determined in Inula viscosa, and the lowest level of 3.0 μg Pb/g was found in Nigella sativa. Calculated daily intakes of Pb of most analyzed herbs were high; most of them are higher than recommended values by the world health organization (WHO). Fortunately, the herbs that contain the highest Pb levels are the less commonly used medicinal herbs in Jordan. The mean Pb levels in the most commonly, commonly and less commonly used herbs in Jordan are 13.9, 13.1 and 16.9 μg Pb/g, respectively. The average dietary intake of Pb through a mixture of these medicinal herbs consumption, assuming 5.0 g herbs is consumed daily, is 79.5 μg Pb/day, which is higher than the maximum daily limit allowed by WHO. We conclude that most of the medicinal plants consumed in Jordan contain significant amount of Pb, and therefore, people of Jordan should not consume large amounts of these herbs.     

Preparation of antibodies and development of an enzyme immunoassay for determination of atrazine in environmental samples

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed and optimized for atrazine determination in soil at different depths (0–10, 10–20, and 20–30 cm) before and after 48 h of application, corn shoot and cow milk samples collected from Dina farm, Egypt. This assay was based on a specific polyclonal antibodies (PAb) raised by immunizing New Zealand rabbits with an immunogen prepared by coupling 3-{4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine-2-yl} thiopropanoic acid to bovine serum albumin (BSA) via N-hydroxysuccinimide (NHS) active ester method. The sensitivity (estimated as IC₅₀value) was 17.5 μg mL^?1 with a detection limit of 0.1 ng mL^?1. The maximum atrazine concentration was found in soil especially in the deepest layer (325 and 890 μg kg^?1 before and after application, respectively). Atrazine concentration in corn shoot was 333.28, μg kg^?1 dry plant, while there was no detectable amount in milk. All samples screened by ELISA were validated by gas chromatography mass spectrometer procedure (GC/MS). Good correlation was achieved between the two methods (r = 0.997 for soil and 0.9814 for plant). This study demonstrates the utility and convenience of the simple, practical and cost–effective ELISA method in the laboratory for analysis of environmental samples. The method is ideal for the rapid screening of large numbers of samples in laboratories where access to GC/MS facilities, is limited or lacking.     

Social support and managerial affective responses to job stress

This research examines the moderating or buffering effects of two social support variables—support from the work group and from the supervisor—on the relationships of role conflict and ambiguity to intrinsic job satisfaction, job involvement and job anxiety. Data were collected from a sample of 89 middle-lower managerial personnel in a large, heavy equipment manufacturing firm in the Midwest. The moderated regression technique was used in data analysis. Significant interactions were obtained between the role variables and both social support variables. The results were in the predicted direction for positive work outcomes (i.e. job satisfaction and involvement) and contrary to prediction for negative work outcome (i.e. job anxiety). Implications of the findings for future research, the management of stress and leadership behaviour are discussed.     

Heavy Metals Monitoring using Bivalves from Mediterranean Sea and Red Sea

The concentrations of heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pd and Zn) were measured in the Bivalves (Modiolus auriculatus and Donax trunculus) collected from the Egyptian coasts of Mediterranean Sea and Brachiodonates sp. from the Egyptian coasts of Red Sea. The average concentrations of the heavy metals analyzed exhibited the following decreasing order: Fe > Zn > Cu > Mn > Ni > Co > Pb > Cd for both Mediterranean Sea and Red Sea. The analyses of Cd, Co, Ni, Pb, and Zn showed higher average concentrations for samples collected from Red Sea than that collected from Mediterranean Sea, while Fe, Cu and Mn showed the reverse results. Fe was used as a normalizing agent for all studied metals and exhibited presence of two locations from each of Mediterranean Sea and Red Sea have anthropogenic inputs of heavy metals. These results suggest that the coastal area in both Mediterranean Sea and Red Sea of Egypt might be considered relatively unpolluted with heavy metal.     

Influence of biomass density and food to microorganisms ratio on the mixed culture type I methanotrophs enriched from activated sludge

Methanotrophic based process can be the remedy to offset the wastewater treatment facilities increasing energy requirements due to methanotroph's unique ability to integrate methane assimilation with multiple biotechnological applications like biological nitrogen removal and methanol production. Regardless of the methanotrophic process end product, the challenge to maintain stable microbial growth in the methanotrophs cultivation bioreactor at higher cell densities is one of the major obstacles facing the process upscaling. Therefore, a series of consecutive batch tests were performed to attentively investigate the biomass density influence on type I methanotrophs bacterial growth. In addition, food to microorganisms(F/M), carbon to nitrogen(C/N) and nitrogen to microorganisms(N/M) ratio effect on the microbial activity was studied for the first time. It was clarified that the F/M ratio is the most influencing factor on the microbial growth at higher biomass densities rather than the biomass density increase, whereas C/N and N/M ratio change, while using nitrate as the nitrogen source,does not influence methanotrophs microbial growth. These study results would facilitate the scaling up of methanotrophic based biotechnology by identifying that F/M ratio as the key parameter that influences methanotrophs cultivation at high biomass densities.