Stvaranje biogenih amina pod uticajem tkivnih enzima i pH smeše pripremljene za proizvodnju sirovih kobasica

The purpose of this paper was to clarify the influence of tissue enzymes and pH value in the mixture prepared for the production of raw sausages on the formation of biogenic amines (histamine and tyramine). A meat mixture very similar in composition to the typical fermented sausage (40% of beef, 40% of pork and 20% of pork fat tissue) was prepared, and divided in to three parts. The pH value of these portions was adjusted to 5,5; 6,0 and 7.0 through the addition of acetic acid, water and sodium hydrocarbonate solution, respectively. The samples were then radiodecontaminated (5 kGy) to exclude the possible influence of native microflora and stored at 18-22° C. The histamine and tyramine contents were determined immidiately and on the 0th, 5th, 10th and 15th days of storage. The obtained results showed that the initial contents of biogenic amines in the fresh meat mixtures were low: 1,05-1,16 μg of histamine and 1,82-2,04 μg of tyramine per gram of mixture. The final contents of these two biogenic amines, created after storing under conditions similar to the normal processing conditions in the production of this type of fermented sausages (two weeks at 18-22° C) also were low and unimportant for the hygienic safety of sausages (1,64-1,88 џд of histamine and 2,26-2.94 μg of tyramine per gram of the mixture). From the results presented the general conclusion could be drawn that enzymatic activity of the meat itself does not contribute very much to the total biogenic amines formed in the fermented sausages. However, comparison of the relative biogenic amine contents in the three groups of samples revealed that pH value of the meat exerts great influence on the intensity of amino acids decarboxylation and on the activity of enzymes which catalyze the formation of biogenic amines.Glavni cilj preduzetog istraživanja bio je da se sagleda uticaj tkivnih enzima i pH vrednosti smeše pripremljene za proizvodnju sirovih kobasica na obrazovanje biogenih amina (histamina i tiramina). Pripremljena je smeša, sirovinskog sastava tipičnog za nadevfermentisanih kobasica (40% govedine, 40% svinjetine i 20% svinjskog masnog tkiva) i podeljena u tri dela, a zatim je svakom delu posebno podešena pH vrednost dodatkom sirćetne kiseline (na pH 5,5), vode (na pH 6,0), odnosno rastvora natrijumbikarbonata (na pH 7,0). Sva tri dela smeše su zatim radiodekontaminirana jonizujućim zračenjem (5 kGy) kako bi se isključio uticaj postojeće mikroflore i uskladištena pri temperaturi od 18-22° C. Sadržaj histamina i tiramina u ovako uskladištenim uzorcima određivan je posle 5, 10 i 15 dana. Dobijeni rezultati su pokazali da je početni sadržaj ispitivanih biogenih amina u svežem mesu bio nizak: 1,05-1,16 mg histamina i 1,82-2,04 mg tiramina po gramu smeše. Krajnji sadržaj ovih amina, nakon skladištenja u uslovima bliskim onim u uobičajenoj proizvodnji ovih kobasica (dve sedmice pri 18-22° C) takođe je bio nizak i sa gledišta higijenske ispravnosti bez većeg značaja (1,64-1,88 mg histamina i 2,26-2.94 mg tiramina po gramu smee). Iz dobijenih rezultata može se izvesti opšti zaključak da enzimska aktivnost mesa ne doprinosi značajno obrazovanju biogenih amina u fermentisanim kobasicama. S druge strane, na osnovu poređenja relativnog sadržaja biogenih amina u tri grupe uzoraka različite pH vrednosti, može se zaključiti da pH ispoljava snažan uticaj na brzinu dekarboksilacije aminokiselina, odnosno na aktivnost enzima koji katalizuju obrazovanje biogenih amina

Health Risks associated with residual pesticide levels in fish reared in purified wastewater from slaughterhouse

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThe main objective of the present research was to determine the concentrations of the selected pesticides in muscle, liver and skin of common carp. Fish were sampled in two different seasons from fish pond which received previously treated slaughterhouse wastewater. Pesticides including etridiazole, chloroneb, trifluralin, propachlor, chlorothalonil, hexa-chlorocyclopentadiene, atrazine, simazine, alachlor, metribuzin, metolachlor, DCPA, cyanazine, chlorobenzilate, endrin aldehyde, cis permethrin and trans permethrin were determined by using a GS-MS method. Many of pesticides were not determined or determined in low concentrations. Propachlor was found in muscle, skin and liver. The recommended acceptable daily intake was higher in comparison with the estimated daily intake for examined pesticides via fish reared in treated slaughterhouse wastewater. It is very important to maintain the safety of the fresh fish produced in wastewater in order to ensure food safety and avoid health problems in humans

Health Risks associated with residual pesticide levels in fish reared in purified wastewater from slaughterhouse

The main objective of the present research was to determine the concentrations of the selected pesticides in muscle, liver and skin of common carp. Fish were sampled in two different seasons from fish pond which received previously treated slaughterhouse wastewater. Pesticides including etridiazole, chloroneb, trifluralin, propachlor, chlorothalonil, hexa-chlorocyclopentadiene, atrazine, simazine, alachlor, metribuzin, metolachlor, DCPA, cyanazine, chlorobenzilate, endrin aldehyde, cis permethrin and trans permethrin were determined by using a GS-MS method. Many of pesticides were not determined or determined in low concentrations. Propachlor was found in muscle, skin and liver. The recommended acceptable daily intake was higher in comparison with the estimated daily intake for examined pesticides via fish reared in treated slaughterhouse wastewater. It is very important to maintain the safety of the fresh fish produced in wastewater in order to ensure food safety and avoid health problems in humans

Optimizing street mobility through a netlogo simulation environment

The routes and streets make it possible to drive and travel through the cities, but unfortunately traffic and particularly congestion leads to drivers losing time while traveling from one place to another, because of the time it takes to transit on the roads, in addition to waiting times by traffic lights. This research introduces the extension of an agent-oriented system aimed at reducing driver waiting times at a street intersection. The simulation environment was implemented in NetLogo, which allowed comparison of the impact of Smart traffic light use versus a fixed-time traffic light

SCHOOL AS A LEARNING ENVIRONMENT – INSTRUMENT AND TEACHERS' PERCEPTIONS

Educational research is often focused on examining the factors that influence student achievement. Teaching quality is the most important among these variables, but it is postulated that many school constructs are also relevant for student outcomes. One of them – school as a learning environment – is the focus of this paper. The aim of the research was to develop, test and describe scales that measure school as a learning environment, as well as to use these scales to assess teachers’ perceptions about their school as a learning environment. The following scales were examined: Interpersonal relationships and social climate in school; Innovation, vision and school development; Organization of school work; Learning as a value in school; and School leadership. The sample included 2401 teachers from 125 schools whose perceptions were assessed through a questionnaire. The results of the Principal Component Analysis (PCA) showed that the data support the existence of three instead of five scales, i.e. that the scale Innovation, vision and school development is not adequate, and that the scales Organization of school work and School leadership represent one scale in the eyes of the teachers. The reliability of the scales obtained from PCA is satisfactory. Teachers in Serbia are very satisfied with the variables that describe school as a learning environment, although there is room for improvement of interpersonal relationships and employee motivation.Publishe