Figure shows the topographical image of irregular silver nanoparticles synthesized

Figure 4 shows the topographical image of irregular silver nanoparticles synthesized by S. cumini, C. sinensis, S. tricobatum and C. asiatica. The particle size of the silver nanoparticles synthesized by commercial plant powder was found to be 53 nm, 41 nm, 52 nm and 42 nm, corresponding to S. cumini, C. sinensis, S. tricobatum and C. asiatica, respectively. Figure 5 shows the FTIR spectrum of Ag NPs. The FTIR showed the presence of bands at 1620 cm−1,1633 cm−1,1641 cm−1 and 1637 cm−1, corresponding to S. cumini, C. sinensis, S. tricobatum and C. asiatica, respectively. Synthesized Ag NPs are identified as amide I and arise due to a carbonyl stretch in the amide linkages of the proteins. The FTIR results thus indicate that the secondary structure of the proteins is not affected as a consequence of reaction with the Ag+ ions or binding with the silver nanoparticles. This result suggests that the biological molecules could possibly perform a function for the formation and stabilization of Ag NP in an aqueous medium. It is well known that proteins can bind to Ag NP through free amine groups in the proteins  [17], and, therefore, stabilization of the Ag NP by surface-bound proteins is a possibility.
Antimicrobial activity of silver nanoparticles synthesized by commercial plant powders was investigated against various pathogenic organisms, such as S. aureus, P. aeruginosa, E. coli and K. pneumoniae, using the well order Ro3306 method. The diameter of inhibition zones (mm) around each well with silver nanoparticle solutions is represented in Table 2. The highest antimicrobial activity of silver nanoparticles synthesized by C. sinensis and C. asiatica commercial plant powders was found against P. aeruginosa (16 mm). The lesser antimicrobial activity of silver nanoparticles synthesized by both C. sinensis and C. asiatica was found against S. aureus (8 mm) and E. coli (8 mm), and the S. tricobatum against K. pneumoniae (8 mm). S. cumini and C. asiatica did not show a zone of inhibition against K. pneumoniae.

Conclusion
We have reported order Ro3306 the synthesis of silver nanoparticles by S. tricobatum, S. cumini, C. asiatica and C. sinensis extracts, which provide simple and efficient ways for the synthesis of nanomaterials. Silver nanoparticles prepared in this process are quite fast and of low cost. The characterization of Ag+ ions exposed to these plant extracts by UV-vis and XRD techniques confirm the reduction of silver ions to silver nanoparticles. The AFM image suggests that the particles are irregular shaped. The FTIR study suggests that the protein might play an important role in the stabilization of silver nanoparticles. Biological synthesized silver nanoparticles could be of immense use in the medical field for their efficient antimicrobial function.

Introduction
Nowadays, scientists constantly search for newer measures to obtain better food quality  [1]. The quality and safety control of food, especially in the food industry, play an important role in both health and the economy. Therefore, a great deal of research is being done in the area of food safety and freshness. The current progress in nanotechnology and its applications, especially in the life sciences, has attracted much attention towards applying nano material and nanostructures for the preservation of food, in the hope of achieving more reliable, safer, cheaper and less chemically influenced techniques for improving health and the longer shelf life of food. One of the most important items in the daily diet of most people is wheat and its derivatives, such as bread, cakes, cookies, and so on. Freshness and shelf life are very important factors in the bread baking industry.
Therefore, many researchers have been looking for methods that conveniently assess the degree of food fungal growth at a very early stage, and well in advance of becoming visible  [2].
As a living organism, the activation of fungi in bread is accompanied by the production of some gaseous products, such as CO2. Thus, detection of these gases at very early stages can set off alarms regarding the start of food decay. It is expected that sensing methods based on nanotechnology will help to detect gases on a molecular scale.