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Nitrofurans: the hidden killer in aquatic products

What are the nitrofurans
Nitrofuran antibiotics mainly refer to furazolidone, nitrofurazone, nitrofurantoin and furaltadone, which are a class of broad-spectrum antibiotics. It can inhibit the gram-negative and gram-positive bacterial when in low concentration, and kill those bacterial when in high concentration. In addition, this drugs is also effective when deal with protozoon and fungus.

nitrofurans structure

How do the nitrofurans work
Nitrofurans affect the metabolic system of carbohydrates by inhibiting the enzyme system of microorganisms, and also prevent the initiation of translation, so as to achieve the effect of bacteriostasis and sterilization. The mechanism of action of nitrofurantoin is unique. It is reduced by bacterial flavin protein to active intermediates that inhibit bacterial ribosomes and other macromolecules. Thus inhibits protein synthesis, aerobic energy metabolism, DNA and RNA synthesis and cell wall synthesis.

Warning: hazards of nitrofurans in food
Nitrofurans are commonly used as veterinary drugs for antibacterial and anti-inflammatory purposes, and are widely used in the prevention and treatment of dysentery, enteritis and coccidiosis in animals and poultry. Nitrofuran drugs and their metabolites can cause canceration and gene mutation in experimental animals. After excessive intake of nitrofuran residues in food, the main hazards to human body are gastrointestinal reactions and hypersensitivity reactions. Nitrofurans are genotoxic, mutagenic and carcinogenic, and their metabolites bind to proteins stably with a long half-life. Countries around the world have banned the use of nitrofuran drugs, which cannot be detected in food.

How to detect the nitrofurans in aquatic products
Because nitrofurans are rapidly metabolized and rarely remain in edible tissues, it is not meaningful to directly determine the parent compounds of drugs. However, the protein-binding metabolites formed by nitrofuran drugs in animals can be retained in the edible tissues of animals for a considerable period of time. Therefore, the EU takes the metabolites as the target analytes to indirectly achieve the purpose of detecting nitrofuran residue.

Nitrofuran metabolites can be hydrolyzed under acidic conditions, and then through a series of processes such as derivatization, extraction and purification, and finally detected by HPLC-UV, LC-MS, LC-MS /MS or ELISA.

Chromatographic instrumentation is the most commonly used method for the detection of furan drugs. It is based on the chromatographic column to different substances adsorption capacity is different, the column components are separated, and then into the detector for detection. It is characterized by accurate qualitative and quantitative analysis, strong anti-interference ability, low detection limit and rapid determination. But at the same time, the pretreatment process of this method is complex, time-consuming, expensive and requires high operation technology.

ELISA uses the specific antibodies of AOZ, AMOZ, SEM and AHD, has higher precision, more sensitive response and stronger specificity and shorter testing time, also has not high technical requirements and the advantages of high flux measurement, also need in the process of extraction derivatization, detection can reach 0.1 ppb, the defect is false positive results, anti-jamming capability is relatively weak, and the higher price of kit.

Colloidal gold immunochromatography (Lateral flow immunochromatography) is an effective method for rapid on-site screening of drug residues due to its advantages such as simple, rapid and intuitive operation, as well as the fact that the kit can be stored at room temperature without detection instruments.

Some detail in sample pretreatment
The commonly used derivative reagents include: 4-carbonyl benzaldehyde (4-CBA), 2-nitrobenzaldehyde (2-NBA) and 4-nitrobenzaldehyde (4-NBA). The derivation conditions are generally 37 oC 16 h, or 60 oC 1 h.

Introduction of our products
E1701 - Furazolidone Metabolite Test Kit
E1702 - Furaltadone Metabolite Test Kit
E1703 - Nitrofurazone Metabolite Test Kit
E1704 - Nitrofurantoin Metabolite Test Kit
E4701 - Nitrofurans Metabolites Test Kit

Information Category