The Development Of Portable Food Safety Instruments For Fast Analysis And The Application In Food Analysis

The problem of food safety is the social focus presently. This problem is also serious in our country. A lot of illegal activities in food processing, such as making fakement, using impurity contents and non-edible or rotten raw materials can't be prohibited usually. Some poisonous and harmful food that pesticide remains and food additive standard exceed is common in people's daily life. Accidents of food safety take place repeatedly. They threaten customers healthy and safety directly.Our country has already signed up to WTO, the developed countries already set up their own supervision and management systems that are relatively advanced. They make limit for food import by establishing non-tariff trade barriers such as technology barriers. So, settlement of the problem of food safety well will not only influences the people's daily life but also do help to improve the status of the nation in the world and to add foreign exchange earnings.In order to protect consumers' healthy, avoid trade barriers by the developed country in international trade, improve the competitive ability of our food in the international market, it is very important to exploit the prompt detection technologies based on food safety and the requirement forinternational trade on food. At present,The conventional methods need complicated sample pretreatment, consume reagents and last a long measuring period. The thesis analyses the current situation and trend of the problem of food safety in our country and the development of the instruments both at home and abroad. On the basis of studying typical instrument structure and characteristic both at home and abroad, we confirmed the whole structure of the portable Food Safety Instruments for Fast Analysis, which is made up of the lighting system, the examining system, control system and recording instrument.The several high-brightness LEDs is used for light source, according to the characteristics of the high-brightness LED, utilizing various kinds of optics knowledge, we have calculated and designed the optical system, it have a very simple design and many features such as inexpensive price, long life time, aseismatic and anti-cauterization performance;the examining system made up of a light-to-frequency converter of TSL series, which result in a good repeatability and save analytical time greatly;the control system made up of singlechip of AT89C52, a LCD module and several keys. The analyzer can be used not only independently, but also can communicate with PC, and the operating software (The language is 51 assembly language and C Language) is friendly to the operator, and has strong data processing functions.For examining the whole performance of the analyzer, according to the knowledge of spectral analysis and spectral analysis principle, we do the experiment of the spectrum for the formaldehyde and nitrite in kinds of foods,utilizing the Portable Food Safety Instruments for Fast Analysis that we IIdesigned. The analysis of each sample can be completed in 30 minutes. Whose result is compared the result of standard experimental utilizing the national standard approach, and the result shows that there were no apparent differences. Therefore, it is more eligible to quick detection of food.The lower limit of formaldehyde is 1.0 mg/kg, the calibration curve (correlation coefficient: 0.997) is linear within the range of 1.0-100.0 mg/kg;the lower limit of nitrite is 2.0 mg/kg, the calibration curve (correlation coefficient: 0.998) is linear within the range of 2.0-200.0 mg/kg.