Read the following text and answer the question.

    Blueberries, cranberries, and huckleberries-like dark skinned bunch grapes-contain restorative, a potential anticancer agent. That's a new finding from preliminary data from ARS collaborative studies with Rutgers University-New Jersey and Ag Canada, Kent ville, Nova Scotti. Restorative protects dark-skinned bunch grapes from fungal diseases and provides health benefits to consumers, including protection from cardiovascular disease. The compound's anticancer potential warranted its examination in other fruits.

    Using gas chromatographic and mass spectrometric procedures, the scientists measured the restorative content of 30 whole fruit samples of blueberry, cranberry, huckleberry, and related plants representing 5 families and 10 species of Vaccination fruit. They found that several samples contained varying amounts of the compound. Analysis of extracts of the skin, juice/pulp, and seed of muscadine grapes showed that its concentration in fruit skin was highest. Levels in the juice/pulp were much lower than in either skin or seeds. Researchers are continuing to analyze more Vaccination and muscadine samples. Future research goals will include enhancing production of restorative in selected species.

How many fruit samples are used in the research?