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Food Safety and You: Choosing the Best Sanitizer

Dr. Randy W. Worobo · Assistant Professor of Food Microbiology ·Cornell University/ NYSAES ·Geneva, NY 14456

_Sanitation of a food plant, no matter how large or small, is essential in controlling microorganisms. By incorporating a comprehensive sanitation program into your plant processing procedures, you achieve three things.

Firstly and most importantly, it protects consumer health. Secondly, it minimizes economic loss due to spoilage, which results in added profits for the producer. Finally, sanitation prevents contamination of foods with materials that may offend the consumers' aesthetic sensibilities. It is important to realize that a sanitation program alone cannot ensure food safety nor prevent product spoilage. Rather, additional steps must be taken, such as: effective cleaning of equipment and raw product; proper operating procedures and practice; and ensuring proper controls over all factors that can lead to food contamination.

There are three main groups of sanitizers that are used for plant sanitation. These are:

• Chlorine and Chlorine Compounds
• Iodine Compounds
• Quaternary Ammonium Compounds (quats or QACs)

Chlorine and Chlorine Compounds

The chlorine group is the most widely used in food processing plants. There are numerous chlorine compounds that can be used during sanitation. The form of chlorine that is responsible for its germicidal properties is hypochlorous acid.

The selection of chlorine compound(s) best suited for your plant is based on the applicable regulatory restrictions which exist for your processing plant and the time required to kill 99 percent of the exposed microorganisms for various concentrations. Chlorine gas and the hypochlorites have very similar killing rates but special precautions must be taken with chlorine gas since it is toxic. Chloramines require 12 to 15 times longer to achieve a 99 percent reduction, but are longer lasting compared to hypochlorites. Chloramines are well suited for situations where long contact times are possible.

Several factors affect the germicidal properties of chlorine solutions. With chlorine solutions, more is NOT always better. When using hypochlorites, the pH of the chlorine solution becomes more alkaline with more hypochlorite. With a solution of 1000 ppm of hypochlorite (pH 11-12), it will take three times as long to kill the same number of bacteria as a 25 ppm solution of hypochlorite (pH 8-9). In general, the lower the pH, the more effective the germicidal properties are. For instance, a pH of 6.0 is three times more effective than pH 8.0.

Another factor that must be taken into account when using chlorine compounds is that the presence of organic matter negatively affects the killing power of the chlorine solution. Chlorine in the water binds to organic matter and no longer possesses germicidal properties. Therefore, it is important to monitor the chlorine present in any soaking tanks. Recommended starting concentrations are 100-200 parts per million (ppm) (1/2 oz per gallon of water) for equipment, and 1000-2000 ppm for floors and walls (6 oz per gallon of water).

The final factor that plays a major role in the effectiveness of chlorine compounds is temperature. Germicidal activity increases with temperature. As the chlorine solution temperature approaches the boiling point though, less and less chlorine is soluble in the water, and the concentration decreases. Therefore, the most frequently recommended temperature range for treatment is 100°F-122°F.

Iodophors

Iodophors are sanitizing agents that contain iodine. The iodine itself is responsible for the germicidal properties. Unlike chlorine solutions, iodophors react less with organic matter, do not irritate skin at recommended concentrations, and possess an amber color that serves as a visual indicator that the solution still contains active iodophor.

Some of the disadvantages of iodophors are that the solutions can stain surfaces or plastic, cause discoloration in starchy foods, are only active at acidic pHs (i.e., less than pH 7.0), are not effective against spores, are more expensive than chlorine compounds, and are not stable above 120 to 140°F.

Iodophor solutions are ideal for hand and foot dips and are recommended for equipment made of aluminum or other soft metal (25 ppm concentration).

Quaternary Ammonium Compounds (quats or QAC)

This group's attributes include: leaves a residue that inhibits molds and other microorganisms; stability to heat; effective over a wide pH range; non-corrosive and non-irritating; leaves no taste or odor; and is less affected by organic matter than is chlorine. Some of the unfortunate drawbacks of quats are that some bacteria are not inactivated by quats (gram-negative organisms, for instance) and are incompatible with soap, anionic wetting agents, or some inorganic phosphates.

Ten Desirable Characteristics when Choosing a Sanitizer:

1. Kills microorganisms quickly.

2. Is safe and non-irritating to employees.

3. Is safe for consumers and acceptable to regulatory agencies.

4. Is rinseable.

5. Has no adverse effect on food being processed.

6. Is economical.

7. Tests easily for solution concentration.

8. Is stable in concentrated form and in solution.

9. Is compatible with other chemicals and equipment.

10. Is readily soluble in water.