I wouldn’t get too enthralled by B-Corp certification – it’s just private sector governance without regulation and, basically, a cash generating scheme. In the same way that other certifications such as Grüne Punkt, B Corp will accept certification for single products, allowing less than reputable brands to portray themselves as good corporate citizens.
None of their standards are legally enforceable and no one is liable for damages if a company fails to meet them. If a company as reviled as Nestlé can get B-Corp certification – then it doesn’t speak well to the value of this scheme other than as a marketing device.