Sanitizers are used as a part of the cleaning process, to reduce the load of microbial contaminants that may be present on milk/food contact surfaces. Most dairy sanitizers,when used appropriately, destroy a broad spectrum of microorganisms. Sanitation procedures should be performed after washing and immediately before processing.Most chemical sanitizers are inactivated by organic matter and are, therefore,ineffective on poorly cleaned surfaces. Dairy sanitizers should be non-toxic, non-corrosive, quick acting, be easily applied and economic. Sanitizers commonly used in the dairy industry may be classified as 1) thermal 2) radiation or 3) chemical Sanitizers.
i. Thermal Sanitizers
The effectiveness of thermal sanitizing depends on a number of factors including:microbial contamination load, humidity, pH, temperature and time.
Steam: The use of steam as sanitizer has limited application, as it is relatively expensive. It is also difficult to regulate and monitor contact temperature and time.Besides these, the by-products of steam condensation may hamper cleaning operations.
Hot Water: This is commonly used in many dairy plants. It involves circulating water of at least 77° C (determined at the outlet) for at least 5 minutes. Applying higher temperatures (>85° C) for longer times (10-15 minutes) are recommended to allow heat penetration into areas that are hard to reach. Hot water treatments should be followed by a cooling chemical sanitizer rinse. Hot water will often provide greater destruction and longer milk shelf-life than can be achieved with chemical sanitizers alone.
The main advantages of hot-water sanitization are as follow:
- easy to apply,
- penetrates into cracks and crevices,
- readily available,
- relatively inexpensive,
- relatively non-corrosive, and
- very effective over a broad range of microorganisms.
It also has a few limitations, namely:
- forms films or (or contributes to their formation), thereby shortening the life of equipment or their parts,
- high-energy costs,
- safety concerns for employees, and
- slow process which requires come-up and cool-down time.
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