For specialty food manufacturers across Europe, location equals brand. While Roquefort and gorgonzola cheese might resemble each other in their crumbly texture and unique smell, the former must be made from a specific strand of mold found in the French caves of Roquefort-sur-Soulzon, while the other is produced in the northern Italian regions of Piedmont and Lombardy. If it’s not made in Italy, it’s not gorgonzola.

“Champagne” is perhaps one of the most serious and litigious of these designations; it can only be prepared and produced in the French province that bears its name, using the méthode champenoise—all other bubbly wines are simply “sparkling.” The protection extends to all aspects of the brand. In 2013, the Interprofessional Committee for Champagne Wine preemptively warned Apple that that newest iPhone color could under no circumstances be described as “champagne.”

The European Union’s Protected Designation of Origin status guarantees and safeguards the authenticity of many regional and traditional foods, from celery to cider. Britain currently has more than 60 beverage and food products with protected designations: The long, peppery pinwheel of Cumberland sausage can only be sourced and produced in the English county of Cumbria, and Yorkshire Forced Rhubarb can only be grown in the “Rhubarb Triangle” in West Yorkshire. If the United Kingdom votes in Thursday’s referendum to leave the EU, those protections will disappear, and manufacturers across the globe could start claiming to make Scotch whisky or Stilton cheese, possibly pushing local producers out of business.

Photographer Martin Parr was born in Epsom, England, provenance of Epsom salt, which does not hold any kind of protected designation. A documentarian of British working life, Parr visited manufacturers around the U.K. in the lead-up to the Brexit vote to see how they produce their specialized foods.

WEST YORKSHIRE: Mrs. Bridges Rhubarb & Custard candies are made from Yorkshire Forced Rhubarb, which was awarded Protected Designation of Origin status by the EU in 2010. Martin Parr / Magnum

Forced rhubarb must be grown in the dark, and workers pick the stalks by candlelight to prevent the stems from photosynthesizing, which alters their color and texture. Martin Parr / Magnum

GRIMSBY, LINCOLNSHIRE: Alfred Enderby Ltd is one of the only independent, family-run traditional fish smoking companies left in England. Martin Parr / Magnum

Alfred Enderby produces smoked haddock, trout, salmon, and ingredients for fish pie. Its traditional method of smoking fish is protected by an EU Geographical Indication. Martin Parr / Magnum

OAKHAM, RUTLAND: The Grainstore Brewery produces Rutland bitter, a pale ale with low alcohol content. The beer hails from the East Midlands county of the same name, and it is one of three British beers with protected geographic status. Martin Parr / Magnum

CIRENCESTER, GLOUCESTERSHIRE. The Butts Farm Rare Breeds raises and slaughters Gloucestershire Old Spot Pigs. To label your product “traditionally farmed Gloucestershire Old Spots pork,” the meat must come from these pigs, reared with traditional farming methods.Martin Parr / Magnum

Protections for Gloucestershire Old Spot pigs include guaranteed “ample clean bedding,” prohibitions against tail and teeth clipping, and access to “wallows, dips, or showers.” Martin Parr / Magnum

SAXELBYE, LEICESTERSHIRE. Websters Dairy produces Stilton cheese, which must be made with full-fat pasteurized cows’ milk, from cows grazed in one of three English counties.Martin Parr / Magnum

Both Blue Stilton and White Stilton have protected designation of origin status from the EU. Websters is one of only six dairies that can manufacture Stilton. Martin Parr / Magnum