I am Biju Michael, engaged in selling Polysorbate 20 in Russia, thus, it is extremely important for me to select a reliable supplier of Polysorbate 20.
Size of Team
Member Size of suppliers or manufacturers also plays a very important role; generally number of manufacturers is slightly larger than traders. A complete overseas trade involves a lot of sessions; To perform perfectly, each session requires well-professional persons. A well-founded overseas trading company generally includes online marketing, sales, logistics, purchasing, service, administration departments, etc.
Normally we can scan through the vendor’s web site or some third-party social networking sites to confirm suppliers’ team size.
Google “Company Name”
A renowned company name usually shows a great deal results on Goolge Search, because its company name is frequently searched by their customers or cited by other web sites.
Take “Foodchem International Corporation” as an example, as has been showed in the below picture, there comes out more than 298,000 searching results on Google. 
Supply of Products
Compared with Manufacturers, other than service advantage, main advantage of trading companies lies in being able to provide various kinds of products. For example, when we would like to order Polysorbate 20 as well as several other food ingredients, trading companies becomes the best choice, since unlike factories, traders can provide one-stop service and have greater bargaining powder which permits a lower price.
Of course , we can purchase Polysorbate 20 directly from manufacturers if the volume is large enough, but it won’t be a bad choice if we keep in touch with some large-scaled traders. Because once your long-term-cooperate factory is in short of Polysorbate 20 , we can turn to trading companies, who can help to find other suppliers shortly or even direct supply Polysorbate 20 in no time.
As far as we know, big suppliers of food additives and ingredients can basically provide more than 100 kinds of products, among which, Foodchem International Corporation are able to supply overseas customers more than 300 kinds of food additives and ingredients, plant extracts, nutritional supplements, apis, etc.
Certificate
A formal operation supplier of food additives normally passes ISO certificate as well as other well-known certificate like halal, kosher, ect.
Company Name
As a professional trader or manufacturer of food additives, normally its company name has food, chemical, additives or other key words in it. Other trading companies who have affairs in all fields, usually performs unprofessionally.
Shipping and Payment
In order to meets different needs of buyers, according to intercoms, Polysorbate 20 suppliers often provides several payment ways, such as FOB, L/C, D/P, T/T and so on.
Exquisite Website
Qualified Polysorbate 20 suppliers tend to have more elaborate and professional web site, with better user experiences and less bugs or faults.
Sales of Supplier
There are tons of suppliers of Polysorbate 20 in China, thus, supply scale should be important, Polysorbate 20 suppliers with a certain size suppliers tend to have more bargaining power, in some country, we can even find their Polysorbate 20 supply volumes through customs data.
http://www.foodadditives.com/Emulsifiers/Polysorbate-20.html