Food Safety -- part I
Food safety. It doesn't immediately jump out as our most dramatic environmental health problem. But the facts say otherwise:
The purpose of this section is to define potentially hazardous food under the California Health and Safety Code. "Potentially hazardous food" under most cases must be stored below 41 degrees F. or above 140 degrees F. These foods have the highest potential for spreading foodborne illness. Its fundamental legal definition is:
A legal exception to this definition is Clostridium botulinum. Because of the extreme toxicity of its toxins, rapid and progressive growth is not necessary for botulism. Any growth or toxin production of this organism represents a significant risk.
Because of the significance of potentially hazardous food, the following conditions (defined by law) allow us to determine foods that are not potentially hazardous:
Try the links to the California Health and Safety Code (click first on "food safety" given at the bottom of this page, and then select "CURFFL"), and look at the additional distinctions provided under the law. It is one of the most important definitions you will ever work with in the field.
A. Infections 1. Salmonellosis Salmonella typhimurium Salmonella enteritidis 2. Campylobacter Campylobacter jejuni 3. Listeriosis Listeria monocytogenes 4. Hepatitis type A = infectious 5. Brucellosis Undulant Fever 6. Trichuriasis Trichuris thrichiura 7. Anisakiasis Anasakidae family B. Intoxications (primarily exotoxins) 8. Staphyloccoccus Staphyloccoccus aureusIncubation period of 2-4 hours.9. Botulism Clostridium botulinum 10. Perfringens Clostridium perfringens C. Poisonous plants/animals 11. Favism Vicia faba 12. Snake root Eupatorium is a weed. Cows feeding on this weed give milk that can cause illness. It is an allergic reaction that is not life threatening. 13. Paralytic shellfish poisoning 14. CiguateraRelated to paralytic shellfish poisoning, fish feeding in red tides can accumulate toxins that cause illness.15. Scombroid Scombridae family D. Others 16. agent: Vibrio parahemolyticus reservoir: oceans (variety of seafood) transmission: poorly cooked seafood symptoms: diarrhea, abdominal cramps (rarely fatal) 17. agent: Bacillus cereus reservoir: soil transmission: especially cooked rice at room temperatures symptoms: sometimes vomiting, sometimes diarrhea 18. agent: Clostridium perfringens (anaerobic sporeformer) reservoir: soil; also, GI tract of healthy humans or animals transmission: spores survive normal cooking, then germinate, multiply, and produce toxins symptoms: diarrhea, nausea; usually no vomiting or fever 19. agent: Copper poisoning transmission: copper in prolonged contact with acid foods or carbonated beverages (e.g., improper vending machines) symptoms: vomiting and weakness in < 1 hour (often minutes)
A. Pasteurization (pasteurization is not sterilization, but a practice designed to kill pathogens without destroying taste): 1. Ultra Pasteurization: >280 deg. F for >2 seconds 2. Ultra High Temperature: 191-212 deg. F. for 1 to .01 seconds (UHT) 3. High Temp. Short Time: 161 deg. F for 15 seconds (HTST) 4. Holder pasteurizer: 145 deg. F for 30 minutes B. Food and Temperatures: 5. Thermometers: required in refrigerators. should be: readily visible at the warmest part of the unit accurate to 1 degree Centigrade 6. Stem designed to check food temperatures (or probe) typically has metal stem thermometer: with temperature readings at top of thermometer Restaurant operators must have on the premises. 7. Maximum used to check temperatures in dishwashing machines registering thermometer: 8. Refreezing: frozen foods may not be thawed and refrozen (exception: when food is cooked or processed after thawing). C. Canning operations: 1. soaking reduces spoilage bacteria and washing: 2. sorting consistent quality of product and grading: 3. blanching: direct contact with hot water or steam destroys enzymes (reducing chemical changes) softens tissues to fit in can washes away "raw" flavor 4. exhausting: heat foods in cans prior to closing can produces partial vacuum 5. sealing: secures lid on can hermetic double seam when can cools, lids pull in (concave) 6. retort closed vessel for "sterilization" of food processing: 240 degrees for 30 minutes 7. cooling: quick cooling minimizes thermophilic bacteria potential for water contamination through seams (water must be disinfected)When canning is indequate, thermophilic spoilage agents can survive. These agents are not pathogenic (causing illness), but they can ruin the flavor and edibility of the food. Examples include: flat sour spoilage, thermophilic anaerobe, and sulfide spoilage agents.D. Dishwashing: 8. Manual 3 compartment sink: method: detergent and warm water: good at removing, not killing bacteria most important step in dishwasing rinse: removes detergent before sanitizer sanitizer: a "polishing" step hot water (180 deg F, 30 seconds) chemicals and warm water (75 deg F): chlorine: 100 ppm for 30 seconds quaternary ammonia: 200 ppm for 1 minute iodine: 25 ppm for 1 minute 9. Machine see NSF standards method: (National Sanitation Foundation) wash: 140-160 deg. F rinse: 180 deg F, 10 seconds, 15-25 psi (water pressure) or chlorine rinse (50 ppm)
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