40 Questions
What percentage of foodborne disease cases are associated with temperature abuse?
50%
Why are infants, the elderly, and people who are ill more susceptible to foodborne pathogens?
They have a lower resistance to pathogens
What is the minimum core temperature that meat should be heated to for 2 minutes to prevent foodborne disease?
70°C
Why is it important to wash hands before and after handling raw meat?
To prevent cross-contamination of other foods
What can significantly lower a person's resistance to foodborne pathogens?
A severe bout of influenza or the common cold
Why should raw meat be stored in small containers in refrigerators?
To allow for faster cooling and prevent pathogen growth
What is the primary source of microorganisms in the deep muscle tissues of healthy, slaughtered livestock?
Few, if any microorganisms
What should not come into contact with cooked or ready-to-eat foods?
All of the above
What is the main reason for bacterial load on the surfaces of the carcass during meat production?
Extra handling of the carcass
Why is it important to clean the raw meat preparation area before and after cooking?
To prevent cross-contamination of other foods
Where do microorganisms come from during the processing of meat?
From multiple sources, including exterior surfaces, gastro-intestinal tract, equipment, and workers
What is the purpose of controlling contamination opportunities during meat production?
To reduce the bacterial load on the surfaces of the carcass
What is the recommended standard for meat with a good shelf-life?
102-104 organisms per cm2
What is the main method of controlling contamination during meat production?
Using properly cleaned equipment and utensils
What is the primary reason for the removal of skin during meat production?
To expose the sterile surface of the muscle
What is the significance of the gastro-intestinal tract in meat production?
It is a source of microorganisms
What is the approximate number of organisms found per cm2 of hide on live cattle?
10^7
Why is it important to remove hides or fleece in a manner that avoids contact with the carcass?
To prevent contamination of the meat
What is the main reason why cattle from feedlots may carry more faecal bacteria and less soil organisms?
The Husbandry practices used in the feedlot
Why should hands and equipment that touch the outside of the hide be thoroughly cleaned before coming into contact with the carcass?
To prevent contamination of the meat
What is the approximate number of bacteria found per gram of soil?
10^7
Why is it important to only present relatively clean animals for slaughtering?
To reduce the risk of contamination of the meat
What is the main reason why the modern trend is to not slaughter excessively dirty animals until they have been cleaned?
To reduce the risk of contamination of the meat
What is the approximate number of 'coli forms' found per gram of faeces?
10^8
Why should carcasses not be rinsed?
Because it spreads contamination rather than removing it
What is the main challenge to the meat industry in relation to hygiene?
To minimize external contamination of meat with micro-organisms
What can occur when un-split carcasses are washed?
Contamination of clean areas
Why is fast chilling important for microbiological quality?
To restrict microbial growth
What is a consequence of wet carcasses being warm?
Rapid spoilage
What is a risk of contamination during chilling?
Contact with dirty floors and walls
Which of the following organisms are associated with meat spoilage?
All of the above
What is a compromise required in the chilling process?
Between fast chilling and preventing cold-shortening of pre-rigor muscle
What is the primary difference between intoxication and in vivo intoxication in the context of foodborne illness?
The location where the toxin is produced
Which of the following bacteria is commonly found in the nasal passages of healthy humans?
Staphylococcus aureus
What is the minimum number of staphylococci required to produce a sufficient amount of toxin to make people ill?
1,000,000 (10^6)
Where can bacteria responsible for human illness originate from?
From healthy or ill humans, animals, or plants, and from a normal or contaminated environment
What is necessary for foodborne illness to occur?
The presence of a causative agent in the food
Which of the following is an example of a pathogen that can be present in small numbers as part of the microorganisms on live, healthy animals?
All of the above
Why is it more likely to become ill when large numbers of organisms are present in the food?
Because the chance of becoming ill is greater when large numbers of organisms are present
What is the primary factor that determines the likelihood of foodborne illness?
The number of bacteria present in the food
Study Notes
Contamination in Meat Production
- Healthy livestock have few microorganisms in their deep muscle tissues, but their exterior surfaces (hide, hair, skin, feathers) and gastro-intestinal tracts are naturally contaminated with various microorganisms.
- Each processing step in meat production provides opportunities for contamination with microorganisms from the exterior surfaces, utensils, equipment, and gastro-intestinal tracts.
- Contamination can occur from:
- Exterior surface of the animal
- Contents of the gastro-intestinal tract
- Equipment and utensils
- Workers' garments and hands
- The abattoir itself (e.g. air, floor drains)
- Water (and ice, if used)
- To control contamination, proper cleaning and sanitation of equipment and utensils, as well as personal hygiene, are essential.
Microbial Contamination Sources
- Exterior surfaces of healthy animals and birds are naturally contaminated with large numbers of microorganisms (e.g. 10^7 organisms per cm2 of hide).
- Soil and faeces are also significant sources of microbial contamination (e.g. 10^7 bacteria per gram of soil, 10^9 organisms per gram of faeces).
- The hide, fleece, or skin of the animal is a major source of carcass contamination (pathogens and spoilage bacteria).
Meat Handling and Hygiene
- Only relatively clean animals should be presented for slaughter, and the cleanliness of livestock depends on husbandry, weather, and climate.
- Cattle from feedlots may carry more faecal bacteria and less soil organisms than those from pastures.
- Excessively dirty animals should not be slaughtered until cleaned, and carcasses should not be rinsed, as this can spread contamination.
- Un-split carcasses should not be washed, and split carcasses should only be partially washed under low pressure.
Chilling and Contamination
- Fast chilling is essential to restrict microbial growth, but too rapid chilling can lead to cold-shortening of pre-rigor muscle and loss of tenderness.
- Contamination can occur during chilling from carcasses touching each other, contact with dirty floors and walls, and from the air.
Spoilage Bacteria
- Several types of bacteria are associated with meat spoilage, including Pseudomonas, Brochothrix, Moraxella/Acinetobacter, lactobacilli, and psychrophilic Enterobacteriaceae.
- Different organisms grow and spoil meat depending on growth requirements, packaging, and storage conditions.
Foodborne Illness
- Foodborne illness occurs when a causative agent (chemical, physical, or biological) is present in the food, and the agent must be present in sufficient numbers or concentration to cause illness.
- Events necessary for foodborne illness to occur include:
- The causative agent must be present in the food.
- The agent must be present in sufficient numbers or concentration.
- A sufficient quantity of food containing the agent must be ingested.
- People with low resistance, such as infants, elderly, and those with compromised immune systems, are more susceptible to foodborne illness.
Sources of Foodborne Disease
- Temperature abuse (inadequate cooling or heating) is a major contributor to foodborne disease, including:
- Leaving foods at room temperature for several hours.
- Storage at too high a refrigeration temperature.
- Storage of foods in large containers that cool slowly.
- Not heating meat to a core temperature of at least 70°C for 2 minutes.
- Other causes of foodborne disease include:
- Poor sanitary methods of preparation and storage.
- Failure to wash hands and clean utensils.
- Cross-contamination of raw and cooked foods.
Learn about the sources of contamination in meat production, from the exterior surfaces of livestock to each processing step after slaughter.
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