BLBS102-c41 BLBS102-Simpson March 21, 2012 14:25 Trim: 276mm X 219mm Printer Name: Yet to Come
41 Microbial Safety of Food and Food Products 795crops; hence, it is important to ensure that this type of fertilizer is
pathogen-free prior to use. The second stage of control measure
is to prevent contamination and growth of pathogenic organisms
during harvesting and transportation of food products. It is gen-
erally believed that control of microbial contamination early in
production is more effective than control measures applied at a
later stage of production. However, in cases when the presence
of pathogens cannot be eliminated during the production stage,
processing procedures that are designed to control the presence
of pathogens must be implemented. A combination of intrinsic
factors, (i.e., factors associated with the properties of the food)
and extrinsic factors (i.e., factors associated with external con-
ditions) is often used during processing and storage to control
microbial growth or survival in foods (Bibek 1996). Intrinsic
factors such as the pH, water activity, and food components can
promote or inhibit microbial growth or survival. These prop-
erties can be used in combination with extrinsic factors such
as heat, preservatives, irradiation, and storage conditions (e.g.,
refrigeration, relative humidity, and gaseous atmosphere).
Currently, there are several food preservation technologies
available for controlling microbial growth and survival. The
most commonly used technologies for controlling microbial
growth include application of low temperatures such as refrig-
eration or freezing, reduction of water activity of the food by
drying, curing with salt or increased sugar level, pH reduction
by acidification or fermentation, use of food preservatives, and
modified atmosphere techniques. Other preservation technolo-
gies designed to inactivate foodborne organism include heat
treatment such as sterilization, cooking, retorting, pasteuriza-
tion, irradiation, and the use of hydrostatic pressure and pulse
light. Also, use of packaging materials and adequate sanitation
of the food production or processing environment can be used to
limit entry of microorganisms into the food product and prevent
recontamination of processed foods (Gould 1989, Hall 1997).
The use of a combination of preservation techniques, often re-
ferred to as the hurdle concept, can be very effective in con-
trolling microbial growth. A combination of suboptimal levels
of the growth-limiting factors can be very useful where higher
levels of one of the factors can be detrimental to the quality of
the product. The most important hurdles used in food preserva-
tion include high or low temperature, water activity (aw), redox
potential (Eh), acidity (pH), preservatives such as sulfite, nitrite,
and sorbate, and the use of competing microorganisms such as
lactic acid bacteria. The application of an appropriate combina-
tion of these hurdles can improve the microbial stability, sensory
and nutritional qualities, and safety of the foods.FOOD SAFETY PROGRAMS
Traditional approaches to controlling the safety and quality of
foods involve inspection of foods after production or processing
for compliance with general hygienic practice, and where appro-
priate, foods are sampled for laboratory testing. This approach
does not ensure food safety since reliance on visual inspection
and testing of finished products cannot guarantee the absence of
harmful pathogens in food. A more effective food safety con-
trol program, called the hazard analysis critical control point(HACCP) program, was introduced to the food industry in the
early 1970s, and various food safety regulations and trade bodies
worldwide endorsed its use as an effective and rational approach
to assurance of food safety. HACCP is a systematic approach
to hazard identification, assessment, and control. The benefits
of the HACCP approach to ensuring food safety include the
following:
The food industry has a better proactive tool for ensuring
the safety of foods produced.
Potential food safety problems can be detected early.
Food inspectors can focus more on verifying plant controls.
More effective use is made of resources by directing atten-
tion to where the need is greatest.
A significant reduction in the cost of end product testing is
achieved.There are seven key principles of HACCP. Principle No. 1
includes hazard analysis to identify the microbiological, chem-
ical, and physical hazards of public health concern. Raw ma-
terials processing procedures, including packaging and storage,
are assessed for microbiological hazards. The second principle
is to determine the procedures or points in the food operation
where hazards can be controlled effectively. These are called
the critical control points (CCPs). The third principle includes
the establishment of critical limits that separate acceptable from
nonacceptable limits. The fourth principle involves the devel-
opment of a system to monitor the CCPs so that the limits are
not exceeded. The fifth principle is to determine what corrective
actions to take when the CCPs are exceeded. The sixth principle
includes the establishment of procedures for verifying that the
HACCP program is working as expected. The seventh princi-
ple involves the documentation procedures and records for all
aspects of these six principles. These HACCP principles have
received worldwide recognition, by governments and the food
industry. Many industrial organizations have adopted this food
safety program as a means of controlling food safety hazards.
One of the most successful food safety programs at the con-
sumer level is the FightBac program developed by the Partner-
ship for Food Safety Education (PFSE), formed in 1997. This
nonprofit organization provides education on safe handling of
food to the public. The key features of the information on safe
handling of food in the FightBac program are summarized in
Table 41.5. Further information on this program can be found
in the FightBac website (www.fightbac.org). Implementation of
these safe food-handling procedures by consumers can prevent
the occurrence of foodborne illness.FUTURE PERSPECTIVES ON
FOOD SAFETYFoodborne disease is preventable, provided control measures
to prevent contamination of the food supply are implemented
at various stages of the food chain, from the farm to the point
of consumption. On-farm food safety programs include control
measures for preventing contamination of plants, animals, and
plant and animal products that are produced for human consump-
tion. Implementation of effective environmental sanitation, good