Escabeche is made by frying fish or vegetables in oil and then poaching it in vinegar-based brine. Ceviche is the method of cooking seafood in citrus juice. Both citrus juice and vinegar are very acidic, usually between 2 and 3 on the ph scale. Bacterial growth is retarded at a ph of 4. Pickling has long been used as a preservation method for meats and vegetables.