Skills of find maleic acid suppliers and manufacturers
I am Chen Li Tien, engaged in selling maleic acid in Russia, thus, it is extremely important for me to select a reliable supplier of maleic acid.
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. 
History of Supplier
History counts for a lot, a supplier with long history in the maleic acid industry has a wealth of experience to accurately grasp the maleic acid market, most of unexpected problems can be solved timely and accurately. The Chinese government gives all the enterprise a issued business license, from which history of enterprises can be found. Under such a fierce competition of maleic acid market, enterprises who can survive over five years can normally be trusted.
The picture below shows the license certificate of Foodchem International Corporation, China's leading supplier of food additive and food ingredients with establishing year of more than 8.
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.
Certificate
A formal operation supplier of food additives normally passes ISO certificate as well as other well-known certificate like halal, kosher, ect.
Location
Generally cargo takes ship delivery; thus, sustainable trading companies tend to set their sites in coast cities, such as Shanghai, Qingdao, and Tianjin in China.
Google "Website"
While Googling a company website, there will be attached links along with the website on result page. It is an effective and reliable route to judge company scale and brand awareness since not a single company is able to impact Google's objective valuation towards any company. 
Exhibition
maleic acid suppliers will never ever lose the opportunity to communicate with customers face to face on exhibitions. Although with rapid development of the network, some people choose not to attend exhibitions, while substantial companies still avail these opportunities to meet their clients and looking for potential clients.
Therefore, exhibitions provide a efficient solution to find maleic acid good suppliers: Visit suppliers' websites to see their participation in the exhibitions.
Sales of Supplier
There are tons of suppliers of maleic acid in China, thus, supply scale should be important, maleic acid suppliers with a certain size suppliers tend to have more bargaining power, in some country, we can even find their maleic acid supply volumes through customs data.
