If you sell it in an oil mill, you don't need any documents. If there is an industrial and commercial inspection near your home, you can apply for a health permit and a business license. If it is to be supplied to shops or supermarkets, the management is not strict, and generally no one will check it. You can sell in bulk without a license. If you sell as a regular manufacturer, you need a certificate. You should need a business license, a food circulation license and a hygiene license. The staff also need a health certificate.