Cheese fly

Cheese fly (Piophila casei) is a species of fly that is best known for its role in the production of certain traditional cheeses. The larvae of the cheese fly, often referred to as cheese maggots, are deliberately introduced to cheeses to produce varieties such as Casu marzu, a traditional Sardinian sheep milk cheese. The presence of the larvae causes the cheese to ferment and decompose, creating a soft texture and a strong flavor that is prized by some cheese enthusiasts.

Biology and Lifecycle

The cheese fly is a small, dark-colored fly that measures approximately 4 mm in length. It has a cosmopolitan distribution, being found in many parts of the world where cheese is produced. The lifecycle of the cheese fly begins when a female lays her eggs in a cheese that is undergoing fermentation. After hatching, the larvae feed on the cheese, accelerating the fermentation process through the digestion of the cheese's fats and proteins. This activity not only softens the cheese but also increases its level of decomposition, contributing to the unique flavor and texture of the final product.

The lifecycle of the cheese fly is relatively short, with the entire process from egg to adult fly taking just a few weeks under optimal conditions. The rapid development of the larvae is crucial for the production of cheeses like Casu marzu, as it allows for the quick transformation of the cheese's characteristics.

Health Concerns

The consumption of cheese that contains live cheese fly larvae poses several health risks. The primary concern is the potential for the larvae to survive the stomach's acidic environment and cause myiasis, a condition where the larvae infect and live in the gastrointestinal tract of the host. Additionally, there are concerns about the hygiene of consuming a product that has been exposed to fly larvae, as this can lead to the introduction of harmful bacteria and other pathogens.

Regulation and Legal Status

Due to the health risks associated with consuming live larvae, the production and sale of cheeses like Casu marzu are regulated in many countries. In the European Union, for example, the sale of Casu marzu is banned, although it is still produced and consumed in Sardinia under traditional exemptions. The legal status of cheese fly-infested cheeses varies from country to country, with some allowing its production and sale under specific conditions, while others have outright bans.

Cultural Significance

Despite the health risks and legal controversies, cheeses produced with the help of the cheese fly hold significant cultural importance in regions where they are made. They are often considered a delicacy and are consumed as part of traditional festivities and meals. The production of such cheeses is also seen as a way to preserve traditional food preparation methods that have been passed down through generations.

See Also

• Casu marzu
• Fermented foods
• Food safety