Yes it is a must to have a Vendor agreement in place for all vendors you source your groceries from. Such a vendor agreement can be offline i.e. you sign it in person with each vendor or may be online i.e. Vendor terms, which are typically displayed on your website/app and usage of such website/app by the vendor shall bind the vendor to such vendor terms.
Having a vendor agreement/terms in place would help mitigate any risks whether in terms of operations, unforeseen cost implications, or regulatory compliance. Further you can track your vendors and provide the data you need to identify supplier risks so you can take the necessary steps to mitigate them, or choose an alternative vendor.
You can easily verify supplier information, such as qualifications and certifications, track performance, and even look into the supplier’s financials to get a broader picture of their risk level in order to protect your organization.
Vendor agreements also ensure that you reduce costs (having strong relationships with your suppliers, due to effective procedures and processes can help you to negotiate better rates and have access to discounts and incentives that can increase your profit margin), create loyal relationships, increase administrative efficiency and protect your brand.