What is the significance of food toxicological safety evaluation?

Safety evaluation is the use of toxicology.

The basic means of elucidating the toxicity and potential hazards of a chemical substance through animal experiments and human observations, in order to evaluate the safety of these chemicals for human use and to provide a theoretical basis for the formulation of preventive measures, especially sanitary standards.

2) Steps of evaluation: the current food safety in China.

The methods and procedures of sex evaluation are still in accordance with the traditional toxicological evaluation procedures: that is, preliminary work: acute toxicity test, genetic toxicology test, subchronic toxicity test (9d feeding test, reproduction test, metabolic test) chronic toxicity test (including carcinogenic test) (.

3) What factors should be considered in evaluating food safety? 3. All substances that are innovative in China generally require four stages of testing, especially for those whose chemical structure suggests the possibility of chronic toxicity, genotoxicity or carcinogenicity, or those with large output, wide range of use and many ingestion opportunities, all four stages of toxicity tests must be carried out.

Derivatives or analogues that are substantially identical to the chemical structure of a known substance (i.e., a substance that has been evaluated for safety and permitted to be used by the user) shall be subject to the same chemical structure as described in Article 1.

The results of the first, second and third stage toxicity tests determine whether the fourth stage toxicity test is required.

All known chemical substances, World Health Organization.

If the daily allowance per person (ADI, hereinafter referred to as the daily allowance) has been announced, and the applicant has information to prove that the quality specifications of Chinese products are consistent with foreign products, they can be carried out first.

In the first and second stage toxicity tests, if the test results are consistent with the results of foreign products, it is generally not required to conduct a one-step toxicity test, otherwise the third stage toxicity test should be conducted.

3· Pesticides, food additives.

Food new resources and new resource food, irradiated food.

Selection of safety toxicological evaluation test of cleaning and disinfectants for food tools and equipment.

I work as a food toxicologist.

Professional students, the meaning is similar to what the person downstairs said, so I'll talk about the program.

The content and purpose of the four-stage food toxicology evaluation procedure.

Phase 1 Acute Toxicity Test LD50 Objective: To understand the toxicity intensity, nature and possible target organs of the test substance, and to provide a basis for the selection of dosage and toxicity judgment indicators for further toxicity testing.

Phase II 1 Genotoxicity Test, Purpose; It is to screen the genotoxicity of the test substance and whether it has a potential carcinogenic effect.

2. Traditional teratogenic experiments, purpose: to understand whether the test object has teratogenic effect on fetuses.

3. Short-term feeding experiment, purpose: to preliminarily estimate the maximum non-effect dose.

The third stage of subchronic toxicity test (90-day feeding experiment, reproduction experiment, metabolic experiment) Purpose: to evaluate the maximum non-effect dose.

The purpose of the Phase IV chronic toxicity test (including carcinogenic experiments) is to determine the maximum non-effect dose.

Issues to be paid attention to in safety evaluation.

1. The scientific nature of experimental design.

2. Standardization of test methods.

3. Familiar with the characteristics of toxicological test methods.

4. The evaluation results are highly comprehensive.

Objective: To provide a scientific basis for determining safety limits and taking prevention and control measures.

Content: Food safety evaluation is to use the results of toxicological animal tests, combined with population epidemiological survey data to explain the toxicity and potential harm of a specific substance in food, the nature and intensity of the impact on human health, and the safety degree after human exposure.

Scientifically test the possible hazards of any component in a food product and draw conclusions to determine whether the component is acceptable to society or consumers, and to develop standards accordingly.

The methods that can be used for food safety toxicological evaluation include acute toxicity test, genotoxicity test, subchronic toxicity test and chronic toxicity test.

The method of food toxicology evaluation is mainly based on animal experiments, that is, animals are used instead of humans to ingest the food or food components to be tested, and the toxicity and safe intake of the analyte are determined by observing the poisoning performance of animals and detecting the physiological and biochemical indicators of animals, and inferring from humans. In general, there is no strict boundary between poison and non-poison. The same substance, depending on the dose, object and method of use, may be a poison or a non-poison.

Toxicological evaluation of genetically modified foods

1. The application of food toxicological evaluation methods to evaluate the safety of food provides a reliable technical guarantee for our correct understanding and safe use of food additives (including nutritional fortifiers), the development of new food resources and the development of new resources of food and health food, and provides a reliable operation method for us to correctly evaluate and control the safety of food containers and packaging materials, irradiated food, food and food tools and equipment with detergents, pesticide residues and veterinary drug residues.

2. The toxicological evaluation of genetically modified foods includes the comparison of the amino acid sequence similarity between the newly expressed protein and the known toxic protein and anti-nutritional factors, the thermal stability test of the newly expressed protein, and the chain number source test of the digestion stability of the protein in simulated gastric juice in vitro. When the newly expressed protein has no history of safe consumption and the safety data are insufficient, an acute oral toxicity test must be performed.

3. Immunotoxicity testing and evaluation should be carried out if necessary. The toxicological evaluation of newly expressed substances is non-protein, such as fat, carbohydrate, nucleic acid, vitamin and other components, etc., and its toxicological evaluation may include toxicological metabolism kinetics, genotoxicity, subchronic toxicity, chronic toxicity, carcinogenicity, reproductive and developmental toxicity, etc. The specific toxicological tests that need to be carried out are based on the principle of case analysis.

When analyzing the significance of the differences between the experimental group and the control group, the significance of the biological zone should be considered. In addition, if an increase in the incidence of a certain tumor is found in the test group, even if there is no significant difference between the statistical digging group and the control group, it is still necessary to pay attention. For the abnormal changes of some indicators in the experiment, it is necessary to distinguish whether it is the physiological performance or the toxic effect of the test substance when analyzing and evaluating the results.

It should be considered that the administration of a large amount of the test substance may affect the nutrient intake and its bioavailability, resulting in certain toxicological manifestations of the ignition animal rather than the toxic effects of the test substance. When analyzing and evaluating the toxic effects caused by the test substance, the changes in the toxic effects over time at the same dose level should be considered. In addition to the intake of the general population, special and sensitive populations such as pregnant women, nursing mothers, or children should be considered.

As much as possible, the reaction data of the population after contact with the test object, such as occupational contact and accidental exposure, etc., should be collected, and under the condition of ensuring safety, human food testing can be considered in accordance with the relevant regulations. (z) When the animal toxicity test and in vitro test obtain positive results, and the judgment of the results involves whether the test substance can be applied to food, the reproducibility of the results and the dose-response relationship need to be considered. The safety factor is usually 100 times, but it can be increased or decreased according to the relevant influencing factors.

In principle, the data of metabolic tests should be carried out using animal germlines with the same metabolic pathways and patterns as humans as far as possible. In the comprehensive evaluation, the physical and chemical properties, toxicity, metabolic characteristics, accumulation, range of people to be exposed, the amount and scope of use in food, the possible intake of human beings and other factors must be comprehensively considered, and the possible harm caused by the test substance to human health and its possible beneficial effects must be weighed. The basic idea of this question is to start from ensuring human safety, and comprehensively consider the factors that can have an impact on the results of food safety evaluation.

It is necessary to fully consider the biological significance of the experimental indicators, screen the authenticity of the toxic effect, and the influence of time on the toxic effect. In addition, careful consideration should be given to the likely intake of the person and the information that may be available for human consumption. When using the data of animal experiments, the species and metabolic pathways of experimental animals should be fully considered and the similarity between them and humans, and an appropriate safety factor should be used, combined with in vitro experimental data with good reproducibility, and other relevant factors should be considered to make a comprehensive evaluation of the test substances.