Study On Selective Differential Medium, Enzymatic Immunosensor And Smart Tongue In Rapid Detection Of Enterbacter Sakazakii

Enterbacter sakazakii is an opportunistic Gram-negative, foodborne pathogen, which is a member of the family Enterbacter bacteriaceae. Enterbacter sakazakii is considered to causing meningitis, bacteremia or necrotizing enterocolitis. Specially for neonates and infants. The infant powdered milk sales in China also had a high detective rate. The 50～80% infection and transmission path of Enterbacter sakazakii was from powered infant milk and other milk. Enterbacter sakazakii on monitoring, controlling, prevention, diagnosis, and many other quality control and timely and effective implementation of protection is the urgent needs of multi-stage inspection and quarantine department.This research used Selective Differential media, Enzymatic immunosensor and Smart Tongue to detecting Enterbacter sakazakii in three different fast methods. Selective Differential media, which is based on biochemical reaction, is a detection technology. It has successfully combined the reaction of biochemistry and the traditional separation of biochemistry of bacterium, which is easy to observe the result of detection. In addition, there are some advantages-low cost, high sensitivity, specificity and rapidness. Selective Differential media is becoming the main trend of microbial detection. Enzymatic immunosensor based on the specificity of antigen-antibody interactions with electrochemical transduction, have become an attractive subject for food analysis, clinical diagnosis, environmental monitoring and other fields. The Smart tongue applicants a new electrochemical method-----the multifrequency large amplitude pulse voltammetry (MLAPV) which is very useful for discriminating samples in the voltammetric electronic tongue by applying three frequency segments. Multivariate data analysis (MVDA) such as Principal component analysis (PCA), and Soft Independent Modeling of Class Analogy (SIMCA) were often used to analyzing the data from the electronic tongue. With the advantages of rapid detection and simple sample preparation, it seems to be suitable for detecting the liquid cultures of the pathogens.The comments of this paper was described as follows:1 Study on Enterbacter sakazakii Differential MediumBased on the specific enzyme systems and the corresponding metabolisms of Enterbacter sakazakii, according to the resistibility to different antibacterial ingredients, EsDM was designed for the rapid separation, identification or detection of Enterbacter sakazakii. The tests of color effects, plating efficiency, sensitivity and specificity were conducted to evaluate the efficiency of EsDM. The results showed that: EsDM had good selectivity and specificity for Enterbacter sakazakii. After incubating for 16～24 h at 30℃, the Enterbacter sakazakii formed yellow colonies on EsDM. The other strains did not form colonies or form other color colonies. EsDM showed a mean plating efficiency of Enterbacter sakazakii cells of (91.23±2.24)% and its detection limit was 101 cfu/mL. Accordingly, EsDM is useful to detect Enterbacter sakazakii in powered infant milk for kinds of inspection agencies with the strengthens of easily-operated, lower cost, convenience for observation and so on.2 A disposable immunosensor for Enterbacter sakazakii based on MWCNT/Sodium Alginate composite and four-channel screen-printed carbon electrodeA novel Enterbacter sakazakii immunosensor based on HRP-anti-Enterbacter sakazakii immobilized by physical adsorption on the MWCNT/sodium alginate (MWCNT/SA) composite modified four-channel screen-printed carbon electrode surface was successfully fabricated. In this strategy, MWCNT/SA biocomposite acted as the matrix to adsorb and immobilize HRP-anti-Enterbacter sakazakii. The preparation process of modified electrodes was characterized with AFM and CV. The analytical performance of proposed immunosensor toward Enterbacter sakazakii was investigated by CV. Under optimal conditions, the concentration of Enterbacter sakazakii from 103 to 108 cfu mL-1 could be detected, with a detection limit of 2.5×102 cfu/mL (S/N=3). The specificity, reproducibility, stability and accuracy of the proposed immunosensor were also evaluated. The proposed immunosensor showed simply fabricative, economical, efficient and potential application for early assessment of Enterbacter sakazakii.3 Used Smart Tongue to tracing, discriminate and set the SIMCA model of Enterbacter sakazakiiUsed Smart Tongue to tracing and discriminate Enterbacter sakazakii, Salmonella, Shigella spp, Escherichia coli, Staphylococcus aureus, Bacillus cereus. The result showed that:Ag electrode in 10Hz had the trend to discriminate the 5 hour cultures. Therefore we used Ag electrode combined with the frequency of 10 Hz to discriminate the six species of pathogens after 5 hours cultured. The 6 hour cultures can attend a excellent effect and every Mahalanobis distance exceed 2.0. Smart tongue combined with principal component analysis can tracing and discriminate the six species of pathogens, they must be detected in infant formula milk by the national standard. Complying with SIMCA, the Ag electrode in 100 Hz was studied for classifying and identifying the Enterbacter sakazakii. The best models based on the training set for classifying were detected. The discrimination accuracy of the best SIMCA model was 100% for both the training sets and the testing sets.