Here’s a list of foods that contain citric acid In their natural state. This list is growing all the time as I do more research!

• Citrus fruits: all of ’em. It’s strongest in lemons and limes, which are up to 8% citric acid by weight and can even be used to extract the chemical from; sour oranges can also be used, so we assume that the more sour the fruit the higher the citric acid content.
• Berries and soft fruit: Almost all berries with the possible exception of blueberries. Certainly found in: strawberry, raspberry, gooseberry, cranberry, redcurrant, blackcurrant. Redcurrants are one of the worst offenders – redcurrant juice can be used to replace lemon juice in jam recipes!
• Exotic fruits: Pineapple, tamarind
• Stone fruits: Cherries (apparently only a small amount)
• Vegetables: Tomatoes, cayenne peppers (not the same as sweet peppers), Jerusalem artichoke, lettuce (!)
• Wine – as a by-product of fermentation, and to improve clarity
• Cheese – Citric acid is used in the manufacturing process to help clot the milk faster. It may be an integral part of making certain cheeses, especially mass-produced mozzarella, but appears to be a by-product of industrialization for most British cheeses: the traditional method of adding bacterial culture to the milk and allowing it to act slowly does not use added citric acid as far as I know. I don’t, however, know whether citric acid also appears naturally in cheese as a by-product of the bacterial reactions. Conclusion: traditional (read: expensive) cheeses are likely to be safer, but the jury’s out overall.
• Sourdough breads eg. rye bread – as a by-product of fermentation.

Foods which often contain added citric acid

• Stock cubes and concentrates, especially chicken. Check carefully as some brands are fine and others aren’t.
• Soft drinks – almost all of them, especially any fruit-flavored ones. The only citric-free canned soft drinks I’ve discovered are Rubicon brand, which come in flavors like mango and guava.
• Jams and fruit preserves – including fruit yogurts and desserts. Chutneys and pickles are much less likely to contain it as they use vinegar (acetic acid) to preserve and acidify instead.
• Canned tomatoes (NB tomatoes also contain a small amount of citric acid naturally). If you want to use canned tomatoes try organic varieties, which may be citric-free.
• Canned fruit
• Fruit flavour sweets – especially fizzy or sour ones. Citric acid is a major ingredient in sherbet!
• Some ice creams – Only some brands contain it, and they’re often the cheaper ones which use vegetable fats. Citric acid in ice cream acts as an emulsifier to keep the globules of fat separate – this isn’t necessary with “real” ice cream since the milk and cream are emulsified in and of themselves. As a rule, the more expensive the ice cream the less likely it is to contain citric acid; it’s such a terrible hardship to only be able to eat very nice expensive ice cream 😉
• Convenience foods: especially tomato-based sauces.
• Crisps: Only certain flavors, but often the more “complex” ones such as prawn cocktail and cheese and onion. Check the packet as brands vary.
• Mayonnaise – Can be made with vinegar alone, but is most often made with lemon juice.

Eating Out

• Thai food: Shop-bought Thai food often contains lime juice, but Thai restaurant food is usually citric-free since they use Kaffir lime leaves to give an aromatic lime flavor.
• Indian food: Many Indian dishes contain lemon juice and/or tomato. Some Indian food also uses tamarind, which is an exotic fruit containing citric acid. Lime pickle is obviously a no-go area and mango chutney is likely to contain citric acid or lemon juice as a preservative. Tandoori grilled meats are usually fine, as are rice dishes (other than lime pilau, obviously!), breads and some side dishes such as sag aloo and probably most bhajis. Tarka dall (lentil dhal) does contain lemon juice, though I’m not sure about other side dishes.
• Chinese food: Restaurant and takeaway Chinese food is generally OK apart from lemon chicken, sweet and sour dishes, and dishes containing pineapple.
• Mediterranean food (Italian, Greek): Mediterranean food very often contains tomatoes or lemon juice, so investigate menus carefully if you want to eat at a Mediterranean restaurant.
• Middle Eastern food: Middle Eastern restaurants usually have some dishes which are free from citric acid, particularly the charcoal-grilled meat. Some Middle Eastern restaurants also make hummus without lemon juice. However tomatoes turn up in dishes like kisir so check with the waiter before ordering.
• American food: Burger relishes, mustards and commercially made apple pies and desserts often contain citric acid as a preservative. Mayonnaise is almost invariably made with lemon juice although it is possible to make it with only vinegar.
• Traditional English food: Not usually a huge problem except in desserts where berries, lemon and orange are popular and lime is becoming more so. A traditional cooked breakfast barely needs to be altered at all unless you’re a fan of baked beans or fried tomato, and a roast dinner should be completely free of citric acid, especially if you make the gravy yourself (some gravy powders are fine however, including Bisto). Lactose intolerants have a far tougher time with English menus!