Food Quality and Food Safety | Class 12 Home Science Notes

Food-borne Illnesses and Hazards

Food-borne illnesses arise primarily from biological hazards, which include bacteria, viruses, parasites, and pests. Two main types of microbial food-borne diseases are infections and intoxications. Food infections occur when live pathogenic organisms are ingested and multiply within the body, causing illness. Salmonella is a classic example; it resides in the intestinal tracts of animals and can contaminate raw milk and eggs. Proper cooking destroys Salmonella, but inadequate cooking or cross-contamination (e.g., using the same cutting board for raw meat and salad without cleaning) can spread it. Symptoms include diarrhea, fever, and abdominal cramps. Food intoxications occur when bacteria produce toxins in food that remain even after the bacteria are killed. Staphylococcus aureus is a common cause; it is present on the skin, hair, and nasal passages of many healthy individuals and can contaminate food if handlers do not maintain hygiene. Toxins cannot be detected by smell or taste, making such foods deceptively unsafe. Parasites such as tapeworms can infest food, especially pork. Additionally, pests and insects can infest food, leading to contamination. Factors contributing to the emergence of new pathogens include changes in host susceptibility, genetic mutations, changes in eating habits, climate, and globalization of the food supply. Examples of emerging pathogens include Norovirus, Rotavirus, and Hepatitis E, which contribute to a significant proportion of food-borne illnesses. Continuous surveillance and detection methods are essential to control these hazards.

📊 Diagram: Fig. 6.5 shows infestation of food by pests and insects, illustrating physical contamination. Figures 6.3 and 6.4 depict biological hazards including visible pests and invisible microorganisms.

🔗 Connection: Prepares the learner to understand contamination and adulteration concepts, and the broader topic of food quality.