Principles of Food Sanitation

to reduce the growth of halophilic microor-
ganisms. The walls, floors, and ceilings of
ripening rooms and cheese storage areas
should be washed with fungicide solutions.
Increased outbreaks ofL. monocytogenes,
S. aureus, and Yersinia enterocoliticacause
concern because these organisms can attach
to surfaces and cross-contaminate food
products or expose workers to contamina-
tion if surfaces are not cleaned and sanitized
properly. Because disinfectants affect micro-
organisms differently and at different con-
centrations, tests should be conducted to
determine the appropriate disinfectants and
concentrations at each step of the cheese
manufacturing process.

Rapid Assessment of Cleanliness

Paez et al. (2003) evaluated a commercial
ATP-bioluminescence system to evaluate
cleanliness of milking machines, bulk tanks,
rinse water, and milk transport tankers on an
experimental dairy farm. Bioluminescence
results were not reliable for rinse water, so it
was suggested that surface swab evaluations
were also needed for a complete hygienic
assessment.

Summary

Plant layout and construction affect micro-
bial contamination and overall wholesome-
ness of the product. It is especially important
to ensure that clean air and water are avail-
able and that surfaces in contact with dairy
foods do not react with the products.
Soils that are found in dairy plants include
minerals, proteins, lipids, carbohydrates,
water, dust, lubricants, cleaning compounds,
sanitizers, and microorganisms. Effective san-
itation practices can reduce soil deposition
and effectively remove soil and microorgan-
isms through the optimal combination of
chemical and mechanical energy and sanitiz-

ers. This condition is accomplished through

the appropriate selection of clean water,

cleaning compounds, cleaning and sanitizing

equipment, and sanitizers for each cleaning

application. A current trend has been toward

modification of CIP systems to permit final

rinses to be utilized as makeup water for the

cleaning solution of the following cleaning

cycle and to segregate and recover initial

product-water rinses to minimize waste dis-

charges. Every processing facility should ver-

ify the effectiveness of its cleaning and

sanitation program through daily microbial

analyses of both product and various equip-

ment and areas.

Study questions

1. What construction characteristics are
   needed for effective sanitation in dairy
   plants?


2. What temperature is necessary to hot-
   water sanitize dairy processing equip-
   ment?


3. How is chemical sanitizing of dairy
   processing equipment accomplished?


4. What are the two major categories of
   CIP operations?


5. What brushes are best for cleaning
   dairy processing equipment?


6. How can film deposition be decreased
   in ultra-high-temperature heaters?


7. What is a preferred cleaning method
   for lightly soiled surfaces of storage
   tanks for dairy products?


8. How is the processing equipment for
   milk, skim milk, and low-fat dairy
   products cleaned?


9. How is the cream and ice cream pro-
   cessing equipment cleaned?


10. How do soil components from cold
    sources differ from those of burned-
    on deposits with higher protein and
    mineral contents?

296 PRINCIPLES OFFOODSANITATION