Food Safety Risk Analysis

Tour of a Bacterium

Bacteria are single cells too small to see without a microscope. This one, Escherichia coli, is perhaps the most thoroughly studied organism in the world. It is used in genetic engineering and in studies of protein synthesis and the control of gene expression.

	Proteins are made on ribosomes that float free in the cytoplasm.
	Billions of E.coli live in the human intestine.
	Sticking out from the outer surface are pili, by which cells attach to surfaces or other bacteria
	E.Coli is Gram-negative. It has an additional layer of lipid and polysaccharid outside of the cell wall.
	Bacteria reproduce by dividing in half as frequently as every 20 minutes.
	The strong cell wall is a network of polysaccharides cross-linked by short chains of amino acids.
	Flagella rotate like propellers to drive the cell through its environment.
	The cytoplasm is not divided into separate compartments.
	All of the genes are located on a single molecule of DNA. There is no nucleus.

The issues that have been addressed on this site led us to recommend a re-evaluation of Hazard Analysis Critical Control Points/Pathogen Reduction in light of what is known today about risk analysis. While well-intended, HACCP does not carry the hazard analysis step - the initial step of the HACCP process - to its logical conclusion. While it attempts to identify conditions under which potentially hazardous organisms may thrive and thus pose a health threat to human beings, it does not specifically identify which microorganisms at what dose-response levels need to be controlled in order to guarantee food safety. For example, the presence of Salmonella spp. at a concentration of 50,000 cfu/gm in a sample of ground poultry does not indicate an immediate hazard to human health. A more scientific risk analysis would look like this:

Begin with a list of all pathogenic microorganisms capable of causing foodborne disease.
Are these pathogens present in the raw materials of the food product being processed?
If the answer is no, then eliminate the pathogen from further consideration in the process.
If the answer is yes, then does the production process completely eliminate the pathogen?

The possibility that pathogenic microorganisms are contaminating the product after processing cannot be ignored.

If the production process eliminates the pathogen, then eliminate the microorganism from further consideration in the process; if it does not, then:

Did this organism cause problems in the past with identical or related products?
If it did not cause any problems, then eliminate this pathogenic microorganism from further consideration.
If it did cause problems, is it an infectious organism or a toxinogenic organism?
If it is a toxinogenic organism, does it grow in the food product?
If it does not, then eliminate it from further consideration.
If it does grow in the food product, or if it is an infectious organism, then it is a potentially hazardous microorganism that the food production process must control in order to provide food safety.

This approach would place HACCP on a scientific footing and would allow food processors to ignore those microorganisms that are not a threat to food safety instead of trying to provide commercially sterile foodstuffs.

At this point, a controversial argument must be introduced. There are those in the scientific and medical communities who argue that a certain level of pathogenic microorganisms needs to be present in our food supply in order to stimulate the human immune system and keep it healthy. They say autoimmune diseases are at their highest exactly in those countries that work the most diligently to eliminate microorganisms from their food supplies. A causal relationship has not been demonstrated, but further research is merited.

After a true risk assessment has been performed, instead of Step One (Hazard Analysis) of HACCP, the next step is to utilize the principles of quantitative risk analysis in performing Step Three of HACCP, setting criteria for food processing. This step can best be performed by a Process Authority, a disinterested party that can review the entire food processing technology proposed for a specific product and say 'yea' or 'nay' based on precise knowledge of food chemistry and microbiology (and fluid dynamics, thermodynamics, metallurgy, et cetera.)

Introducing quantitative risk analysis into HACCP would follow this path:

Start with a list of potentially hazardous microorganisms as outlined above.
Determine the numbers and kinds of organisms present in raw materials by scientific assay.
Calculate the effects of processing technologies, product composition, viscousity, et cetera, on the contamination of the end product by conducting: (a) storage tests, (b) microbial challenge testing, and (c) mathematical modeling.
This will yield the numbers of pathogenic microorganisms expected to be present in RTE products.
Are these levels acceptable?
If the answer is yes, set the criteria for the food processing technology.
If the answer is no, change the raw materials, process design, product composition, et cetera, until the quantitative risk is acceptable.

If the two procedures outlined above - a quantitative risk analysis of microbial pathogen threat and a quantitative risk assessment to set criteria for process control - are then integrated into HACCP, HACCP would become a truly scientific, risk-based food safety system. HACCP, then, will look like this:

Hazard identification through quantitative risk analysis of microbial pathogens (HACCP Step One)
Identification of operations wherein a quantifiable control can be exercised (HACCP Step Two)
Exposure assessment: (a) storage tests, (b) microbial challenge testing, (c) mathematical modeling
Dose-response assessment
Risk characterization
Risk Management (HACCP Step Three)

Revising the process because of:

New developments in food technology
Newly-emerging foodborne diseases
Changing product formulae (HACCP Step Six).

The newly-revised HACCP model thus eliminates steps four, five, and seven from its current configuration to produce a truly science-based food safety system.