This is the million (billion?) dollar question! If any of you out there ever come up with a safe, all natural cosmetic preservative that works as well as the old standby preservatives (parabens, etc) when in a complete formulation then please do get in touch with me. We will have a business to make together
cossci21: Organic acids, leucidal, and potassium sorbate/benzoate are pretty much all that come to mind and in my view all have ample disadvantages compared to traditional preservatives.
Since Organic Food Chain is an Australian-only organic certifier, and as far as I know there are only a few raw material manufacturers in Australia, if you are looking specifically for OFC certified preservatives you are probably not going to find much, if anything.
If you are able to use US and/or EU organic certified products, you will find a much greater variety.
In the US, products are certified to meet the USDA’s NOP standards. (United States Department of Agriculture National Organic Program (NOP)). A number of so-called third-party certifiers are permitted to certify products - the government sets the standards, but it’s private companies that actually issue the certifications. As near as I can tell from a brief look, Organic Food Chain is the Australian equivalent of a US third-party certifier - they are not affiliated with the Australian government, but they certify to government standards.
In the EU, the organic certifiers I’m aware of are the Soil Association and Ecocert.