Control Measures

Control Measures Focus on safety and quality Food safety control measures -- prevent foodborne illness. Food quality control measures -- maximize shelf-life, slow spoilage, or produce a new product. Processors use a combination of controls One-control system can be harsh making food unacceptable to the consumer. Multiple controls is called the hurdle concept and is commonly used. C 5.01 -- Control Measures

Hurdle Concept Food processors use a combination of control measures called hurdle concept. The three primary control measures are: Controlling water activity and/or pH values of the food. Adding chemicals, such as additives or substances like salt, directly to the food. Adjusting the atmosphere surrounding the food using special packaging methods. C 5.01 -- Control Measures

1a -- Controlling Water Activity Water activity (Aw) Minimum, optimum, and maximum values Yeasts and mold grow at a lower water activity than do bacteria. 0.85 safe cutoff for pathogen growth Based on minimum water activity needed for S. aureus toxin production. C 5.01 -- Control Measures

Water activity and foods Above 0.85 Moist foods Refrigeration or another barrier to control pathogen growth 0.60 and 0.85 Intermediate moisture foods No refrigeration, short shelf-life because spoilage by yeast and mold Below 0.60 Low moisture foods Extended shelf-life without refrigeration C 5.01 -- Control Measures

Controlling water activity Method Foods Hot air drying Solid foods like vegetables, fruit, and fish Spray drying Liquids and semi-liquids like milk Vacuum drying Liquids like juice Freeze drying Variety of foods Adding salt or sugar Soy sauce, jams, salted fish C 5.01 -- Control Measures

1b -- Controlling pH Minimum, optimum, and maximum pH values for microbial growth Yeasts and mold grow at low pH. Pathogenic bacteria do not grow at 4.6 or below. pH controls growth and is not a method to kill pathogens. C 5.01 -- Control Measures

Ways to Control pH Acidification Fermentation direct addition of acid to a low-acid food Use organic acids, acetic, lactic, or citric or add high-acid food to mixture Direct – predetermined amounts of acids added to individual finished product Bath – acid and food combined in large batches and allowed to equilibrate. Fermentation Lactic acid bacteria produces lactic acid. C 5.01 -- Control Measures

Measuring pH pH meter Indicator solutions Indicator paper Titration Digital method but expensive Easy, the MOST accurate, and sanitary Indicator solutions Organic dyes used with dropper Solution turns pink or red in acid; green or blue in base Neutral solution may turn lilac and might be difficult to read Not totally accurate Indicator paper Used by dipping Turns yellow to red in acids; turns green or blue in bases Easy but not completely accurate Titration Add base with know ph to an acid Uses burette Difficult to calculate math so recommended for those with chemistry knowledge C 5.01 -- Control Measures

2 -- Adding Chemicals Preservation method might not prevent growth of all microorganisms. Add chemical preservatives, such as: sorbates benzoates sulfites nitrites antibiotics C 5.01 -- Control Measures

How Chemicals Function? Denature proteins. Inhibit enzymes. Alter or destroy cell walls. Alter or destroy cell membranes. C 5.01 -- Control Measures

Common Chemical Preservatives Mechanism Benzoates Inhibit yeast or mold Sorbates Inhibit mold Propionic acid Sulfites Antioxidant and antimicrobial Nitrites Inhibit C. botulinum Salt Inhibit pathogens, especially C. botulinum Antibiotics -- nisin Antimicrobial in cheese C 5.01 -- Control Measures

Regulating Preservatives Chemical preservatives are food additives. Approved uses and use levels in FDA’s Food Additive Status List. Addressed through product formulation. Processor must carefully control the quantity of food additive for each batch. Processing conditions must be scientifically established and followed C 5.01 -- Control Measures

3 -- Adjusting the Atmosphere Packaging does not control the growth of pathogens, it is limited to the control of spoilage microorganisms. Two functions: Prevents contamination of the food and/or Extends the effectiveness of food preservation methods. C 5.01 -- Control Measures

Types of Packaging Reduced Oxygen Packaging (ROP) – prevents growth of microorganisms to extend shelf-life Vacuum Packaging – air mechanically removed from the package before sealing Modified Atmosphere Packaging – flush with nitrogen, carbon dioxide, and/or oxygen before sealing. Controlled Atmosphere Packaging – retain atmosphere throughout shelf-life using an oxygen scavenger in packaging. C 5.01 -- Control Measures

Packaging – Key Concerns If ROP used, must have barrier to C. botulinum. Barriers include: Water activity below 0.93 with refrigeration pH below 4.6; salt above 10% High levels of competing microorganisms Thermal processing in final container Freezing with frozen storage and distribution C 5.01 -- Control Measures