Fundamental Food Microbiology, Third Edition - Fuad Fathir

40 FUNDAMENTAL FOOD MICROBIOLOGY
multiply and, even from a low initial population, reach a high level and contaminate
large volumes of foods. Also, when processing equipment is used continuously for
a long period of time, microorganisms initially present can multiply and act as a
continuous source of contamination in the product produced subsequently. In some
equipment, small parts, inaccessible sections, and certain materials might not be
efficiently cleaned and sanitized. These dead spots can serve as sources of both
pathogenic and spoilage microorganisms in food. Small equipment, such as cutting
boards, knives, spoons, and similar articles, because of improper cleaning, can be
sources of cross contamination. Salmonella, Listeria, Escherichia, Enterococcus,
Micrococcus, Pseudomonas, Lactobacillus, Leuconostoc, Clostridium, Bacillus spp.,
and yeasts and molds can get in food from equipment (see Chapter 21).
Proper cleaning and sanitation of equipment at prescribed intervals are important
to reduce microbial levels in food. In addition, developing means to prevent or reduce
contamination from air, water, personnel, and insects is important. Finally, in designing
the equipment, potential microbiological problems need to be considered.
J. Miscellaneous
Foods might be contaminated with microorganisms from several other sources,
namely packaging and wrapping materials, containers, flies, vermins, birds, house
pets, and rodents. Many types of packaging materials are used in food. Because they
are used in products ready for consumption and in some cases without further
heating, proper microbiological standards (or specifications) for packaging materials
are necessary. Any failure to produce microbiologically acceptable products can
reduce the quality of food. Flies, vermins, birds, and rodents in food processing and
food preparation and storage facilities should be viewed with concern as they can
carry pathogenic microorganisms. House pets can also harbor pathogens; proper
care should be taken not to contaminate food from this source.
III. CONCLUSION
Microorganisms enter foods from both internal and external sources. Their levels
and types depend on the care used during production, processing, and storage of
foods. Recontaminations of heat-processed foods with pathogens have been associated
with many foodborne disease outbreaks. Proper sanitation at every stage helps
reduce the microbial level normally expected in a food. Normal microbiological
quality of foods is discussed in Chapter 4.
REFERENCES
1. Krieg, N.R., Ed., Bergey's Manual of Systematic Bacteriology, Vol. 1, Williams &
Wilkins, Baltimore, 1984.
2. Sneath, P.H.A., Ed., Bergey's Manual of Systematic Bacteriology, Vol. 2, Williams &
Wilkins, Baltimore, 1986.