Food Safety and Microbial Growth

• Foodborne diseases, adulterants, contaminants, and chemical residues are the topics covered.
• The lecture is for Year 3 Semester I students in Food Quality Management (BST31302).

The Costs of Foodborne Illnesses

• Foodborne illnesses lead to several costs for an operation.
• These costs include loss of customers and sales, loss of reputation, negative media exposure, and lowered staff morale.
• Additional costs are lawsuits and legal fees, staff missing work, increased insurance premiums, and staff retaining.

Cause of Bacterial Food-Borne Illness

• Bacterial food-borne illnesses arise due to multiple factors.
• Improper holding temperature, poor personal hygiene, contaminated equipment, inadequate cooking, and food from unsafe sources contribute to these illnesses.

Biological Hazards

• Biological hazards have the potential to contaminate food.

What Bacteria Need to Grow (FAT TOM)

• Bacteria needs specific conditions for growth, summarized by the acronym FAT TOM.
• Food: Foodborne microorganisms require nutrients to grow, predominantly in protein-rich foods like meat, poultry, dairy, and eggs.
• Acidity: Bacteria thrive in foods with little to no acid; they grow best in a slightly acidic or neutral environment (pH 4.6-7.5). Most bacteria will not grow at pH levels below 4.6 because the environment is too acidic
• Temperature: Bacteria grow best at temperatures between 5°C to 60°C, or the temperature danger zone.
• Time: Foodborne microorganisms require sufficient time to grow; populations can double every twenty minutes.
• Oxygen: Foodborne pathogens are generally aerobic and require oxygen to survive and grow. A few microorganisms like Clostridium botulinum, which causes botulism, can only grow in anaerobic conditions.
• Moisture: Water is essential for microorganism growth. The perishability of food relies on moisture content and water activity level. Bacteria, yeast, and molds grow quickly above a water activity level of 0.86, for example, meats, produce, and soft cheeses
• Foods preserved with salt or sugar, such as beef jerky or jams and jellies, have lower water activity, these products are shelf-stable unless opened.
• Pathogenic bacteria struggle to grow in dry foods where water activity is below 0.85.
• FDA regulations require that canned foods have a water activity of 0.85 or below.

Handling Hazards

• Strategies to handle hazards involve using Prevention(P), Reducing(R), and Eliminating(E) methods.
• The industry focuses on controlling pathogens; this involves interventions compatible with Good Manufacturing Practices (GMP), Sanitation Standard Operating Procedures (SSOP), and HACCP programs.
• Using multiple interventions serves as "hurdles" to control pathogens.
• Pathogen "control" is viewed as more attainable than "elimination".

Preventing Food-Borne Illness

• Food safety relies on everyone's responsibility from producers, processors, and consumers.
• Keep food hot by cooking thoroughly, holding food at 145-160°F, reheating thoroughly, and never leaving food out for more than 2 hours.
• Keep food cold by refrigerating at 4°C (40°F) or lower, and thawing food in the refrigerator.
• Maintain clean food by thoroughly cleaning equipment, utensils, and person and following "sell by" and "use by" dates. -Prevent cross-contamination.

Ten Main Reasons for Outbreaks of Food Poisoning

• Food prepared too far in advance and stored at a warm temperature
• Cooling food too slowly prior to refrigeration
• Not reheating food to high enough temperatures to destroy food poisoning bacteria
• Use of cooked food contaminated with food poisoning bacteria
• Under cooking
• Not thawing frozen poultry and meat for a sufficient length of time
• Cross-contamination from raw food to cooked food
• Storing hot food below 63°C
• Infected food handlers
• Use of leftovers

Food Allergens

• A food allergen is a protein in a food or ingredient to which some individuals are sensitive.
• Allergic reactions can occur when enough of an allergen is consumed.
• Allergy symptoms include nausea, wheezing or shortness of breath, hives or itchy rashes, swelling of body parts, vomiting and/or diarrhea, and abdominal pain.
• Allergic reactions can become serious rapidly; anaphylaxis, a severe reaction, can lead to death.
• The most common food allergens include dairy, eggs, soy, fish, crustacean shellfish, tree nuts, peanuts, and wheat.

Preventing Allergic Reactions

• Service staff should describe menu items to guests, identify allergens, suggest allergen-free items, clearly mark orders, and deliver food separately to prevent cross-contact.

Toxicity in Food

• The idea whether natural food is always good is a misconception; natural foods can be harmful.
• Terms such as 'health,' 'organic,' 'natural,' 'unprocessed,' and 'no added chemicals' do not necessarily mean the food is safer or more nutritious since all food is made of chemicals.

Mushroom and Plant Toxins

• Foodborne illnesses linked with mushrooms are caused by eating toxic wild mushrooms, prevented by purchasing from approved, reputable suppliers.
• Foodborne illnesses linked with plant toxins can be prevented by purchasing plants from approved, reputable suppliers, properly cooking certain plants like kidney beans.

Anti-Nutritional Factors

• These are compounds found in foods (especially plant-based) that can interfere with the absorption or utilization of nutrients.

Phytic Acid

• Phytic acid is common in nuts, seeds, and grains, storing phosphorus in plant tissue.
• It binds minerals like calcium, magnesium, iron, copper, and zinc, reducing their absorption in the intestines.
• Soaking and milling can reduce phytate content.

Lectins

• Lectins are carbohydrate-binding proteins that are highly specific for sugar moieties.
• Lectins affect digestion and may increase chronic disease risk and cause red blood cells to cluster.
• They are antinutrients that can cause upset stomach when plant foods are uncooked.
• Lectins are found mainly in beans and grains.
• Lectins in foods can be decreased through cooking with moist heat, which also breaks down plant starch.

Ways to Decrease Lectins in Foods:

• Boiling
• Fermentation
• Sprouting
• Peeling
• Deseeding
• Pressure cooking

Oxalates

• Oxalate is an organic acid found in plants that may be synthesized by the body.
• Oxalates interfere with calcium absorption and crystalize in tissues if consumed regularly.
• Found in Kale, Spinach, Chard and other heartly leafy greens.
• Calcium and magnesium bind to oxalates in the stomach and prevent them from being absorbed.
• Oxalates present in plants bind with calcium are practically insoluble

High-Oxalate Foods:

• Raspberries
• Dark Chocolate & Cocoa Powder
• Swiss Chard
• Buckwheat
• Tofu, miso & other soya foods
• Beets
• Nuts & Seeds
• Rhubarb
• Spinach
• Potatoes & Yams
• Black Tea
• Wheat Bran
• Beans

Assignment: Microbiological Concerns

• The assignment is to list the name of the microorganism, picture, available food/sources, threat for human's health, and how to control each microorganism.
• The microorganisms listed are Clostridium botulinum, Staphylococcus aureus, Salmonella, Clostridium perfringens, Campylobacter jejuni & coli, Listeria monocytogenes, and Escherichia coli (0157:H7).

Explore factors affecting microbial growth in food, including time, temperature, and water activity. Learn about strategies for extending shelf life and preventing foodborne illnesses. Understand the importance of food safety management systems.