There are many different styles of referencing, so always follow the style guide your institution or journal asks for. As a starting point, cite Foodzone as computer software:
Foodzone (Version 3.0) [Computer software]. (2026). Blackheath, NSW: Nutrition Experts.
Adapt the punctuation and ordering to your required style (APA, Harvard, Vancouver and so on).
Cite the food composition database too
If your work relies on the nutrient values, also reference the food composition database behind them. Each profile names its database under Preferences — see Choose a food database. The government datasets (for example AUSNUT 2023, FoodFiles 2024 and the Australian Food Composition Database) each publish their own preferred citation on their official websites — use that alongside your Foodzone reference.