Flies are a common sight in many environments, especially where food is present. These insects, particularly house flies, pose a significant hygiene concern due to their ability to act as carriers of various undesirable elements. Their frequent movement between unsanitary areas and human food sources makes them potential vectors for contamination, impacting food safety and public health.
How Flies Spread Contamination
Flies transfer harmful substances to food through distinct mechanisms. One primary way is regurgitation, where a fly vomits digestive fluids onto solid food to liquefy it before consumption. This fluid can contain pathogens picked up from other surfaces, directly contaminating the food.
Another method is defecation, as flies excrete waste that carries bacteria and other microorganisms onto food surfaces. Additionally, physical transfer occurs when pathogens and debris cling to the tiny hairs on their legs, bodies, and wings after landing on unsanitary surfaces such as garbage, decaying organic matter, or animal feces. These contaminants are then deposited onto food upon subsequent landings, even with brief contact.
Diseases Carried by Flies
Flies can transmit a wide array of pathogens, leading to various health risks in humans through contaminated food. They can carry numerous types of illnesses, contributing to foodborne diseases. Common bacterial infections include Salmonellosis (Salmonella), Escherichia coli (E. coli), and Shigella.
Symptoms for these bacterial infections often involve gastrointestinal distress such as diarrhea, nausea, vomiting, and abdominal pain. For instance, Shigella can cause dysentery, characterized by bloody diarrhea, fever, and stomach cramps.
Flies can also transmit certain viruses, like poliovirus, and parasitic organisms, including protozoa and helminth eggs, from unsanitary sources. While less common than bacterial transmission, this contamination can lead to various forms of food poisoning and other gastrointestinal issues.
Keeping Flies Away from Food
Preventing flies from contaminating food involves several practical steps for consumers. Proper food storage is crucial, including covering food, storing it in sealed containers, and promptly refrigerating leftovers. This prevents flies from accessing and landing on edible items.
Effective waste management is another important measure. Using trash cans with tight-fitting lids and emptying them frequently reduces attractive breeding and feeding grounds for flies. Maintaining sanitation by keeping kitchen surfaces clean, wiping up spills immediately, and regularly cleaning food preparation areas also helps deter flies.
Installing screens on windows and doors can prevent flies from entering indoor spaces. Fly traps or natural repellents can supplement these efforts to minimize fly presence.