Food Safety Hazards Lecture Notes

Food Safety Hazards

FSH FD43005FP - Microbiology Quality Control

What are Food Hazards?

A food hazard is defined as "Foreign materials or objectionable matters that can contaminate food."
More specifically: A biological, chemical, or physical agent in food with the potential to cause an adverse health effect.

Biological Hazards

Biological contamination in food premises often results from ignorance, inadequate space, or poor practices.
It may not be detectable in early stages but is the most serious, potentially leading to food spoilage, food poisoning, or death.

  • Biological contaminants include bacteria, molds, viruses (microorganisms), and parasites.

  • Examples:

    • Carcasses contaminated with fecal material.

    • High-risk food contaminated with food poisoning bacteria.

Examples of Biological Hazards:

  • Moldy bread

  • Dirty wooden chopping board

  • Dented and Blotted Cans

Pathogens must grow (multiply) in foods to appropriate levels to cause foodborne disease. They need FATTOM:

  • Food (nutrient)

  • Acidity (Favorable pH range)

  • Temperature (Favorable temperature range)

  • Time to multiply

  • Oxygen

  • Moisture (Water)

Examples of Varying Doses of Microorganism Needed to Cause Disease:

  • Shigella dysenteriae: 10^1 - 10^4

  • Vibrio cholerae: 10^3 - 10^9

  • Salmonella typhi: 10^4 - 10^9

  • Salmonella species (non-typhi): 10^5 - 10^{10}

  • Escherichia coli: 10^6 - 10^{10}

  • Clostridium perfringens: 10^8 - 10^9

Example of Biological Contamination During Manufacturing:

  • Recall of Dumex's Mamil Gold Infant Milk Formula - Stage 1 (850g) due to Cronobacter sakazakii bacteria contamination.

Examples of Potential Biological Hazards and Control Measures:

  • Cooked Food:

    • Left at room temperature within 4 hours.

    • Reheat and consume immediately.

  • Food Contact Surface:

    • Not clean after use.

    • Good housekeeping practice is required.

  • Raw Meat:

    • Handle with bare hands.

    • Wash hands and wear disposable gloves.

  • Working Equipment:

    • Did not clean before starting work.

    • Learn proper handling of working equipment i.e. clean and sanitize equipment before and after use.

Physical Hazards

A physical contaminant refers to foreign bodies like pieces of paper, plastic, glass, bone, metal, or string in food.

  • Examples:

    • Small metal pieces in bread

    • Dead insects

    • Hair

Physical hazards in finished products may arise from several sources:

  • Contaminated raw materials

  • Poorly designed or poorly maintained facilities and equipment

  • Improper operation during production

  • Improper employee practices

Examples of Physical Hazards and Their Sources:

  • Metal: Bolts, nuts, screws, sieves, steel wool, metal fragment

  • Glass: Light bulbs, thermometer, glass beaker

  • Wood splinters: Crates, pallets, overhead structures

  • Insect: Environment, electrocutes, incoming ingredients

  • Hair: Meat ingredients, employee, clothing, rodent

  • Dirt, stones, wrapper: Raw materials, poor employee practices

  • Jewelry, band-aid, cigarette: Poor employee practices

  • Feathers: Poor sanitation, inadequate pest control

Examples of Potential Physical Hazards and Control Measures:

  • Packaging Materials: Cellophane tapes, Paper, Plastic, String, Tapes

    • Conduct visual checks.

  • Bait Traps & Pests: Droppings, insect eggs

    • Good Housekeeping Practices in food processing area.

  • Food Equipment Parts: Screws, Bolts

    • Use magnet / metal detector / X-ray to detect. Have preventive maintenance in place.

  • Environment: Dust, Soil

    • Conduct visual check & housekeeping

  • Human: Hair, hairpin, buttons

    • Wear hairnet, personal hygiene check.

  • Building & Fixtures: Rust, cement

    • Conduct thorough check.

Equipment for Detecting or Removing Physical Hazards:

  • Magnet: Removes hazardous metallic metals

  • Metal detector: Detects hazardous ferrous objects larger than 1 mm and nonferrous objects larger than 2 mm

  • X-ray equipment: Detects foreign objects e.g. stone, metal, glass, bone and high-density plastic and rubber

  • Screen or sifter: Removes foreign objects larger than size of openings (mesh)

  • Aspirator: Removes materials lighter than product

  • Riffle board: Removes stones from dry beans and field peas

  • Bone separator: Removes bone chips from meat and poultry products

Chemical Hazards

A wide variety of chemicals are routinely used in the production and processing of food.
Some of these types of chemicals do not represent chemical hazards when used properly, some of them are capable of causing illness or even death if used improperly.
Hence, chemical hazards may also cause foodborne illness.

Chemicals Used in Food Processing:

  • Growing crops: Pesticides, herbicides, defoliants

  • Raising livestock: Growth hormones, antibiotics

  • Production: Food additives, processing aids

  • Plant maintenance: Lubricants, paints

  • Plant sanitation: Cleaners, sanitizing agents

Chemical substances hazardous to health can originate from:

  • Plants (herbs, fruit pits, mushrooms)

  • Animals (fish)

  • Agriculture/industry that may end up in food unintentionally.

Example: Histamine Food Poisoning

  • Excessive histamine accumulation in fish (especially tuna) when the fishes have not been chilled immediately after being caught. The fish become toxic when bacteria (such as Morganella morganii) produce histamine.

Example: Pufferfish Poisoning

  • Occurs when the liver, gonads, intestines and skin of the pufferfish are consumed. These organs contain tetrodotoxin, which if ingested results in a mortality rate of 50%.

Example: Pest Control in Agriculture

  • Pesticides when used in excess may lead to potential risk to health.

Before any chemicals is used in food, it is important to check against food regulations (local and the country going to export to).

Chemicals can be classified in many categories for example:

  • Color additives

  • Food additives

  • Prohibited substances

  • Substance generally recognized as safe (GRAS)

  • Pesticide chemicals

  • Preservatives

Examples of maximum permitted dosage according to Singapore Sale of Food Act:

  • Melamine is 1ppm

  • Nitrite in cured meat is 125ppm

Examples of Potential Chemical Hazards:

  • Unintentionally Added Chemicals: Pesticides, fertilizers, cleaning agent

    • Control Measures: Avoid residual left in food. Thorough washing.

  • Intentionally Added Chemicals: Food preservatives nutritional additives, coloring

    • Control Measures: Check food regulations before use.

  • Chemical Contaminants: Dioxin (environmental pollutants)

    • Control Measures: Strict control of industrial processes to reduce formation of dioxins.

  • Prohibited Substances: Sudan dyes

    • Control Measures: Check legal status. Conduct chemical testings.

  • Toxic Substances: Lead, mercury

Allergens (Naturally Occurring Chemicals)

A food that causes an allergic reaction is called a food allergen.
It’s usually the protein part of the food (also called a food protein) that causes the allergic reaction.
Reaction can be mild (rash, runny nose, swollen lips or itchy eyes).
Reaction can be serious and leads to anaphylaxis. This type of reaction is called anaphylaxis.

Common Allergens:

  • Egg

  • Fish and Shellfish

  • Milk Allergies and Lactose Intolerance

  • Peanut/Tree Nut

  • Sesame Seeds

  • Soy

  • Sulfite Sensitivity

  • Wheat/Cereals/Gluten Allergy and Sensitivity

  • Celery

How Do We Prevent Different Types of Hazard During Food Processing?

We can use different equipment to monitor whether any contamination into the food products or naturally occur chemical in food. For example:

  • Use metal detectors to detect metal pieces in food products

  • Use microbiological testing to check microorganism content in food products

  • Use high performance liquid chromatography (HPLC) in conjunction with mass spectrometry (MS) for identification and quantification of the pesticides present in fresh vegetables and fruit.

Food Contamination

Different Types of Monitoring

Definition of Monitoring:
A device or procedure for observing, detecting, or recording the operation of a machine or system, especially an automatic control system.

The monitoring program must clearly and precisely describe for every monitoring point:

  • Who will perform monitoring, checking or measuring?

  • What will be monitored, a measurement or observation?

  • When will monitoring, checking or measuring be carried out?

  • How will monitoring, checking or measuring be done?

Monitoring can be grouped into either continuous or non-continuous monitoring.

Continuous Monitoring

It is a constant monitoring. This is done with built-in measuring equipment that records continuously.
Computerized equipment systems are an example of continuous monitoring. Usually use in monitoring

  • Temperature

  • Time

  • Relative humidity

Equipment Used for Monitoring

  • Temperature – temperature chart, temperature digital display

  • Metal pieces – metal detector

  • Temperature – time & temperature data logger

  • Moisture – in-line moisture sensor

  • Humidity – humidity data logger

Non-Continuous Monitoring

It is what the majority of operations primarily use. This monitoring occurs at scheduled intervals. An example of non-continuous monitoring is using a properly calibrated thermometer to measure the temperature of every batch of chicken soup during cooking or chiller & freezer temperature.
It can be a routine measure in place to check raw materials, in process & end product.

Non-continuous monitoring is basically used under 3 circumstances:

  1. To test ingredients where microbiological, chemical or physical conditions are unknown or require testing for approval prior to processing.

    • Microbiological testing

    • Moisture analysis

    • pH checking

    • Water activity analysis

      • Aw meter

      • Moisture analyzer

      • pH meter

Equipment Used for Monitoring

  • To check whether the ingredients meet the product specifications during receiving.

  • Examples of different equipment (magnet, metal detector, aspirator, riffle board)

    • Particle size analyzer

    • Aspirator

    • Sieve shaker

  • Chemical testing

    • Elisa kits – product checking

    • Protein swap & ATP – cleanliness checking on equipment & environment

      • Elisa kits for allergen & preservative checking

      • ATP

  1. In-process monitoring

    • pH checking using pH meter

    • Brix content using refractometer

      • Handheld pH meter

      • Handheld refractometer

      • Desktop refractometer

  2. End product monitoring

This ensures that the final product not only meets regulatory requirements but also lives up to the manufacturer's promises.
Quality control through product testing extends beyond safety considerations. It plays a pivotal role in maintaining the consistent taste, texture, and appearance of products.
Product testing can help identify defects and ensure that products meet quality and safety requirements before they reach the market.

Equipment Used for Monitoring

  • Metal pieces – metal detector

  • Moisture – moisture analyzer

  • Microbiological testing - incubator

  • Water activity – water activity meter

  • pH – pH meter

Summary

The ultimate objective of a food safety system is to prevent or minimize exposure of consumers to different types of food contamination.