Fuzz in Taiwan about French Fries with green patches at McDonald's

Don't eat lots of green or bitter tasting potatoes or potato products and you'll be perfectly fine! (Courtesy: NDSU)

Taiwan's health authorities will conduct stringent checks of potato suppliers after reports that French fries served at fast food restaurants were found with green patches.

Food and Drug Administration (FDA) official Cheng Wei-chih (鄭維智) said that potatoes can turn green due to exposure to enough light. However, consuming a large amount of green potato can cause nausea, vomiting, and diarrhea as it often contains a toxic chemical called solanine. No regulations regarding the maximum level of solanine are imposed yet, Cheng added.

To ease public concerns about food safety, fast food restaurants in Taipei and Tainan were checked for their potato wedges and no safety concerns were found, Cheng said. Moreover, Cheng urged that green potatoes shall not be sold from the upstream suppliers.

According to Cheng, food vendors which were found to either sell or use potatoes containing solanine can be fined around NT$30,000 (US$993.5) to NT$3 million based on the Act Governing Food Safety and Sanitation.

The scoop of green-tinted potatoes was first posted online by a user of PTT, the largest terminal-based bulletin board system (BBS) in Taiwan. He wrote that his tongue felt weird when he was eating potato wedges at McDonald's and he found there was a green tint in the food.

McDonald’s later responded that the company has adopted strict control measures requiring suppliers and workers to remove green potatoes. However, both McDonald's and KFC argued that the green color found in potatoes exposed to enough sunlight is chlorophyll and not poisonous.

Earlier, another case was reported as a consumer in Tainan complained he was served with potato wedges that had turned green at the Japanese fast-food chain Mos Burger.

PotatoPro's Take

This is what the North Dakota State University says on the safety of green potatoes:

Are green potatoes safe to eat?

Although chlorophyll is a natural plant pigment that is tasteless and harmless, the green of potato tubers should signal us to be aware of another substance that is forming inside tubers. This substance is known as solanine, and it forms when any part of a potato plant is exposed to light.

Solanine is a toxic substance that is produced naturally in potatoes and other plants to aid in resistance of insects and animals. Solanine is present in all parts of the potato plant, including the sprouts, roots, leaves, flowers and fruits.

Solanine has a bitter taste and can cause stomach symptoms such as vomiting and diarrhea if you eat enough of it. If ingested in large amounts, it can cause illness or even death in extreme cases. Because of the bitter taste, most people do not eat enough to get sick. In addition, consumers always should avoid consuming sprouts.

Small tuber sprouts contain the highest levels of solanine to protect new growth and provide solanine to the growing plant. If tubers have sprouts, remove the sprouts prior to cooking and consumption.
McDonald's and KFC Statement

The statement by McDonald's and KFC that the green color found in potatoes exposed to enough sunlight is chlorophyll and not poisonous is rather disappointing.

Although the statement is true, it is misleading: the green colour is a clear indicator the potato has been exposed to light, an important indicator for the potential presence of increased levels of solanine.

Fastfood chains should make sure their french fries do not contain excessive amounts of green potato. Furthermore, would staff in the restaurant not be able to see the green colour if it is extreme?

The Bottom line:
  • Avoid eating eating lots of green potatoes
  • Do not eat potatoes or potato products that taste bitter or cause a burning sensation in your mouth
and you'll be perfectly fine!