الفهرس 
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Abstract
Cancer is the most dangerous disease all over the world. According to a recent report by the World Health Organization, until now, more than ten million cases of cancer are reported per year worldwide, it became so important to put food additives under control and to study the mutagenicity of them. Ames test has come to play a central role in testing for mutagenic/carcinogenic potential of chemicals in most countries. It has proved to be a useful and sensitive test for the detection of mutagenic substances.
The present study investigates the hazardous effects of sodium nitrite and or monosodium glutamate ”MSG” used in manufacture of meat products and chicken cubes, respectively. Mutagenicity of the two food additives was investigated by: Ames/salmonella/microsome mutagenicity test system by using the most sensitive Salmonella tester strains.
In the present study, the mutagenicity of sodium nitrite, mono sodium glutamate salt, pastirma , luncheon and chicken cubes were evaluated after being extracted and tested by Ames test. Bacteria strains used in test were Salmonella enterica Ss. Enterica (Ex Kauffmann and Edwards) (Le Minor and Popoff Serover Typhimurium) , tryptophan auxotroph. Three concentrations of each sample and or salt extract were tested (0.1,10 and 100%), 3 dosages from each concentration was tested (1, 1.5 and 2 ml). The used medium was minimal glucose for mutagenicity test.
The obtained results could be summarized as follows:
1. Proximate analysis of meat products and chicken cubes:
Pastirma and luncheon samples chemical analysis gave same percentage of moisture in the two samples, protein was higher in pastirma rather than luncheon with 7.4 fold, fat content was higher in luncheon rather than luncheon with 8.8 fold.
Regarding to ash content in pastirma and luncheon samples it was higher in pastirma rather than that of luncheon by 2.14 fold. Percent of sodium nitrite that used for making pastirma was (0.525%) lower than luncheon (1.75%) . Fiber content was higher in luncheon product with 4.12 fold, this is because various ingredients that added for making luncheon such as soybean.
Proximate analysis of investigated chicken cubes showed moisture content in tested sample 54.6%, protein content was 4.1% and fat content was 7.16%. Ash content was the highest value (62.8%). The low content of fat as well as protein and the high percentage of ash is an indicator to the low nutrition value of this product.
2. Mutagenic effect of samples extract:
2.1. Mutagenic effect of different concentrations of sodium nitrite extract:
- Absorbance of reverse growth of mutated bacteria after growing on 0.1 % sodium nitrite extract showed very little reverse growth at 1 ml dosage, it gave high reverse growth at 1.5 ml dosage and the absorbance measurement gave highest reverse growth at 2 ml dosage. Previous results showed the significant mutagenic effect of sodium nitrite at 0.1% concentration (100 ppm).
- The effect of the sodium nitrite was more obvious at 10 % concentration, the significant effect was increased and gave the highest effect at 10% sodium nitrite extract. The increment of salt concentration to be 100% caused a decremental bacterial growth , it is due to the high concentration of the salt that couldn’t afford the high salt concentration .
2.2. Mutagenic effect of different concentrations of pastirma extract:
Absorbance of mutated bacterial reverse growth after growing on 0.1 % pastirma extract showed significant mutagenic effect (p<0.05) of pastirma at 0.1% concentration. By increasing sample extract dosage, the reverse growth of the mutated bacteria was increased which means increasing of mutagenicity. The effect of the pastirma extract was more obvious at 10 % concentration , at 1ml dosage the bacterial growth gave a higher growth than in case of 0.1% concentration, meanwhile 100% concentration showed partial effect of osmotic pressure on the bacteria and the effect is obvious as absorbance that gave a decrement level.
2.3. Mutagenic effect of different concentrations of luncheon extract:
Absorbance measures of mutated bacterial reverse growth after growing on different dosages of 0.1 % luncheon extract showed gradual increment trend of the reverse mutation of bacteria is due to the mutagenicity of sample even at low concentration of sample extract, 10% showed increment trend in bacterial reverse growth according to absorbance measurements . At 100% concentration, increasing reverse bacterial growth by 2 folds of negative control treatment was shown. Bacterial growth made a higher growth at the higher dosages, it reached to 0.513 at 1.5 ml dosage and 0.543 at 2ml dosage, the mutagenicity effect is highly significant.
2.4. Mutagenic effect of different concentrations of monosodium glutamate extract:
Bacterial reverse growth after exposing mutated bacteria to salt extract (0.1%) showed higher absorbance than the negative control one,these measurements indicate the mutagenicity of the tested sample after enhancing tryptophan synthesizing that made a reverse mutation. Decrement of absorbance was recorded of bacterial reverse growth on 10% concentration lower than 0.1% concentration but still higher than negative control and gave significant effect . Partial cells destruction due to osmotic pressure effect was noticed and recorded by spectrophotometer by exposing bacteria to 100%.
2.5. Mutagenic effect of different concentrations of chicken cubes extract:
Increment effect of tested sample on the bacterial reverse growth at 1 ml dosage 0.1% was showed, By increasing the sample dosage, the bacterial reverse growth was increased also and the effect was highly significant, high mutagenicity effect which is highly significant comparing to negative control shown at 10% . By increasing sample extract dosage the mutagenicity effect was increased compared to negative control. The effect of the sample on enhancing the amino acid synthesizing system and that reflects the mutagenicity of 100% extract.
from previous results it was concluded that there are high mutagenic effect of (sodium nitrite and monosodium glutamate) at 10% , at 0.1% the salt extract gave low mutagenicity but the effect was significant, the salt high concentration (100%) affect the bacterial cells growth appeared at absorbance measurements.
Cured meats (pastirma and luncheon) gave mutagenic effect and bacterial reverse growth at (100 ppm), by increasing sample concentration the bacterial reverse growth gave highest absorbance at pastirma extract, luncheon extract gave gradual mutagenicity.
Chicken cubes extract gave mutagenic effect and reverse bacterial growth at high and low concentration of sample extract.