PUB 301 Lecture 6 PDF

PUB 301 Lecture 6 The good, the bad, and the ugly Good-important in food production provide better taste and texture Bad-cause of food borne illness: Infection with live organisms Intoxication with bacterial toxins Ugly-cause food spoilage with undesirable ch...

PUB 301 Lecture 6 The good, the bad, and the ugly Good-important in food production provide better taste and texture Bad-cause of food borne illness: Infection with live organisms Intoxication with bacterial toxins Ugly-cause food spoilage with undesirable changes Food Storage Depends whether food item is: Raw Cooked Processed Type of food Meat Fish & seafood Fresh fruits & vegetables Dairy products Eggs & egg products  British supermarkets don't refrigerate eggs In North America eggs destined to be sold on supermarket shelves — called graded eggs — are washed and sprayed with a chemical sanitizer before they are sold to the public to reduce the risk of salmonella infection In the U.K., Grade A hen eggs may not be washed because the process is thought to "aid the transfer of harmful bacteria like salmonella from the outside to the inside of the egg http://www.businessinsider.com/should-you-refrigerate- eggs-2014-7 Factors needed for Bacterial Growth Food (High Protein) Acidity (pH 4.6 - 7.0) Temperature (4 - 60°C) Time (Reproduce every 20 min) Oxygen (presence or absence) Moisture (Aw > 0.85) FAT TOM F Food There are sufficient nutrients available that promote the growth of microorganisms. Protein-rich foods, such as meat, milk, eggs and fish are most susceptible A Acidity Foodborne pathogens require a slightly acidic pH level of 4.6-7.5, while they thrive in conditions with a pH of 6.6-7.5 FDA/Canadian regulations for acid/acidified foods require that the food be brought to pH 4.5 or below T Temperature Food-borne pathogens grow best in temperatures between 5 to 60 °C (41 to 140 °F), a range referred to as the temperature danger zone (TDZ) They thrive in temperatures that are between 21 to 40 °C (70 to 104 °F) T Time Food should be removed from "the danger zone" within two-four hours, either by cooling or heating While most guidelines state two hours, a few indicate four hours is still safe O Oxygen Almost all foodborne pathogens are aerobic, requiring oxygen to grow Some pathogens, such as Clostridium botulinum, the source of botulism, are anaerobic and do not require oxygen to grow M Moisture Water is essential for the growth foodborne pathogens, water activity (aw) is a measure of the water available for use and is measured on a scale of 0 to 1.0 Foodborne pathogens grow best in foods that have aw between 0.95 and 1.0 Regulations for canned foods generally require aw of 0.85 or below Food Spoilage Food spoilage is defined as damage or injury to food rendering in unsuitable for human consumption Food must be considered spoiled if it is contaminated with pathogenic microorganisms or various poisonous agents, such as pesticides, heavy metals etc. In many cases there does not need to be an evident sign of spoilage, the food might look normal and only after eating it or by careful bacteriological and toxicological investigation, one is able to realize the defect Causes of food spoilage Growth and activity of microorganisms Bacteria, yeasts and molds are microorganisms that cause food spoilage. They produce various enzymes that decompose the various constituents of food Enzyme activity: Action of enzymes found inherently in plant or animal tissues start the decomposition of various food components after death of plant or animal Chemical reactions: These are reactions that are not catalysed by enzymes (e.g. oxidation of fat)  Vermin: Vermin includes weevils, ants, rats, cockroaches, mice, birds, larval stages of some insects. Vermin are important due to: Aesthetic aspect of their presence Possible transmision of pathogenic agents Consumption of food Physical changes: These include those changes caused by freezing, burning, drying, pressure, etc. Microbial Growth and Food Spoilage food spoilage from microbes alters food visibly in some cases and in other ways, rendering it unsuitable for consumption involves predictable succession of microbes different foods undergo different types of spoilage processes toxins are sometimes produced algal toxins may contaminate shellfish botulism toxins  Approximately 1/3rd of all food manufactured in world is lost to spoilage Microbial content of foods (microbial load): qualitative (which) and quantitative (how many)  Microbial Growth and Food Spoilage Relationship between food spoilage and quantitative extent of microbial contamination (microbial load) a. Raw milk: sour at 103 - 106 b. Vacuum packed meats: off odour at 106 - 107 c. Aerobically-stored meats/vegetables: off odour at 107 - 108 d. Almost all food, aerobically stored meats: slime at 108 - 109 e. Structural change and decomposition >109 Growth per g or cm2 103 104 105 106 107 108 109 1010 a b c d e Temperature Effect on Bacterial Multiplication Bacterial growth is affected by temperature Generally we try to extend the generation time so that lag phase is longer and log phase has a lower slope 3 2.5 2 1.5 1 0.5 0 1 2 3 4 5 6 Temperature Effect on Bacterial Multiplication 37oC Every 20 min 32oC Every 30 min 20oC Every 1 hr 15oC Every 2 hrs 10oC Every 3 hrs 4oC Every 6 hrs 0oC Every 20 hrs -2oC Every 60 hrs Minimum Growth Temperatures of Foodborne Pathogenic Bacteria Clostridium perfringens 15oC Bacillus cereus 10oC Salmonella 4oC Enterotoxigenic E. coli 4oC Staphylococcus aureus 4oC Vibrio 4oC Clostridium botulinum 3oC Listeria 1oC Yersinia enterocolitica 0oC  Clostridium perfringens – found normally in decaying vegetation, found in meat/poultry, 3rd most common cause of food poisoning in US, killed by heat but heat resistant spores Bacillus cereus – milk, cooked rice: survival of endospores, only 2-5% of foodborne illness Salmonella – contaminated during food processing, or from feces, eating raw foods with eggs Beef, poultry, milk, eggs biggest sources  Enterotoxigenic E. coli – fecal contamination of food/water supplies cause of traveler's diarrhea Staphylococcus aureus – found normally on skin, can grow rapidly in food left at room temperature, some types produce enterotoxin Common in ham, salads (egg, chicken, potato, tuna) Vibrio – undercooked seafood, vibrio cholerae infected water (Cholera)  Celine Roi, who graduated from TMU’s Occupational and Public Health program found a correlation between a specific food pathogen and food poisoning, which scientists had been unable to find in the past Roi’s discovery links a specific food pathogen, Vibrio parahaemolyticus, often found in seafood, to a heightened chance of illness, and more severe or longer illness, when combined with carbohydrates https://theeyeopener.com/2008/10/medical-breakthrough-started-at-ryerson  Listeria – raw milk, raw sprouts, processing plants, deli meats, can grow in the fridge but killed by cooking/pasteurizing Yersinia enterocolitica – common in cooler climates raw milk, undercooked meat, contaminated water Microorganisms and pH Organisms Optimum pH Most bacteria 5.5 – 8.0 Yeast (spoilage) 4.0 – 6.5 Molds (spoilage) 4.5 – 6.8 Minimum and maximum pH for growth of some specific microorganisms Microorganism Minimum Maximum Escherichia coli 4.4 9.0 Salmonella typhi 4.5 8.8 All bacteria 4.0 9.0 Molds 1.5 11.0 Yeast 1.5 8.5 pH Values of Common Food Items Food type Range of pH values Beef 5.1 - 6.2 Chicken 6.2 – 6.4 Milk 6.3 – 6.8 Cheese 4.9 - 5.9 Fish 6.6 - 6.8 Oyester 4.8 - 6.3 Fruits < 4.5 (most < 3.5) Vegetables 3.0 – 6.1 Water Activity Limits for Growth Microorganism Water activity Clostridium botulinum 0.95 Bacillus cereus 0.95 Pseudmonas aeroginosa 0.95 Salmonella spp. 0.95 Staphylococcus aureus (anaerobic) 0.90 Candida spp., Saccharomyces Staphylococcus aureus (aerobic) 0.86 Penicillium spp. 0.82 Most spoilage yeast 0.88 Most spoilage molds 0.80 Osmotic yeast 0.70 Water Activity of Common Food Items Food Aw Bread 0.96 – 0.97 Fresh fruits 0.91 – 1.0 Cheese 0.95 – 1.0 Fresh meat 0.95 – 1.0 Cured meat 0.87 – 0.95 Jam 0.75 – 0.8 Dried fruit 0.55 – 0.8 Dried vegetables 0.2 Crackers 0.1 Classifying Foods: Spoilage Highly perishable: nutrient rich, moist, unprotected by rinds/coverings (e.g. milk, meat) Semi-perishable: Can be stored sealed in containers for long periods as long as they have not been opened, once opened they will spoil within a few weeks (e.g. tomato sauce) Non-perishable: dry foods, can be stored almost indefinitely (e.g. dry pasta, uncooked rice, canned goods) Effect of Water Activity on Heat Inactivation of Salmonella Aw Temp.°C Time (min) 0.995 60 0.18 0.94 60 4.3 Decimal reduction time or D value time required at a certain temperature to kill 90% of the organisms being studied Drier foods need longer cooking times Effect of Medium (Fat Content) on Heat Inactivation of E. coli Medium Thermal Death Point (°C) Cream 73 Whole milk 69 Skim milk 65 Whey 63 Bouillon (broth) 61 Heating time = 10 min  Microbial destruction can be achieved using the concepts of TDT, TDP and D values Thermal Death Time is a concept used to determine how long it takes to kill a specific bacteria at a specific temperature Thermal Death Point: This is defined as the lowest temperature that will completely kill a population of a target microorganism within 10 minutes D-value refers to decimal reduction time (or decimal reduction dose) and is the time (or dose) required at a given condition (e.g. temperature), or set of conditions, to kill 90% of the exposed microorganisms Internal Cooking Temperatures Food Temperature Beef, veal & lamb (pieces & whole cuts) Medium-rare 63oC (145oF) Medium 71oC (160oF) Well done 77oC (170oF) Pork (pieces & whole cuts) 71oC (160oF) Poultry (e.g. chicken, turkey, duck) Pieces 74oC (165oF) Whole 85oC (185oF) Ground meat & meat mixtures (e.g. burgers, sausages, casseroles etc.) Beef, veal, lamb & pork 71oC (160oF) o o Poultry 74 C (165 F) Egg dishes 74oC (165oF) Others (e.g. hot dogs, stuffing, leftovers) 74oC (165oF) http://www.hc-sc.gc.ca/fn-an/securit/kitchen-cuisine/food-aliments-therm-eng.php Heat Inactivation of Thermophilic Bacterial Spores Temp.°C 60 billion spores 50,000 spores C. botulinum thermophile pH 7.0 pH 6.1 100 260 min 1140 min 105 120 110 36 180 115 12 60 120 5 17 Food-Borne Diseases two primary types food-borne infections food intoxications Toxins ergotism toxic condition caused by growth of a fungus in grains aflatoxins carcinogens produced in fungus-infected grains and nut products fumonisins carcinogens produced in fungus-infected corn Exotoxins Produced inside bacteria and secreted – Enterotoxin, Neurotoxin, Cardiotoxin Superantigen: Type I > intense immune response > cytokines > fever, nausea, vomiting, shock (Staph aureus) Membrane disrupting toxin: Type II > lysis of cells by disrupting membrane A-B toxins: Type III has two parts – A is active enzyme toxin that inhibits protein synthesis and kills cell – B binds to surface so toxin is transported across plasma membrane (Clostridium)  Bacteria-Caused Foodborne Illness INTOXICATION (1–12 hrs) INFECTION (6-72 hrs) Staphylococcus Salmonella (chicken) (infected food handler) Shigella (fecal Bacillus contamination) (cooked rice) Campylobacter (chicken) Clostridium (produce, soil) E. coli (ground beef) 80/20 Rule 80% of quality problems caused by 20% of contributing factors known as the “vital few” Others are known as the “trivial many” Hazard Analysis & Critical Control Points (HACCP) Internationally recognized food safety system Used to help ensure the manufacture of safe food products Recognized as the primary means for enhancing food safety throughout the food chain HAACCP – method developed by NASA and Pillsbury Corp to prevent foodborne illness in space 1960s Hazard Analysis & Critical Control Points (HACCP) Designed to: prevent, reduce or eliminate potential biological, chemical and physical food safety hazards, including those caused by cross-contamination During the development of a HACCP system potential hazards are identified and control measures are implemented at specific points in the manufacturing process Hazard Analysis & Critical Control Points (HACCP) Control Point: Any point, step or procedure at which biological, physical or chemical factors can be controlled Critical Control Point: A point, step or procedure in the product- handling process where controls can be applied and a food safety hazard can be prevented, eliminated or reduced to acceptable levels Cooking step (elimination) Chilling step (reduction) CRITICAL CONTROL POINT GUIDELINES At this step of the process Can food become contaminated? Can contaminants increase? Can contaminants survive? Can this hazard be prevented through corrective actions? Can this hazard be prevented, eliminated or reduced by steps taken later in the preparation process? Can this CCP be monitored? How will it be measured and documented? Hazard Analysis & Critical Control Points (HACCP) 7 Standardized Principles 1. Conduct a hazard analysis 2. Determine the critical control points 3. Establish critical limits 4. Establish monitoring procedures 5. Establish corrective actions 6. Establish verification procedures 7. Establish record-keeping and documentation procedures http://www.omafra.gov.on.ca/english/food/foodsafety/processors/haccp.htm Hazard Analysis & Critical Control Points (HACCP) Principle 1: Conduct a Hazard Analysis Process of: identifying the hazards that might affect a particular product in a specific processing operation collecting and evaluating information on the hazards and conditions leading to their presence deciding which are significant to food safety and must be addressed by the HACCP plan Potentially Hazardous Foods Perishable food or drink Cooked or raw animal products Meat, dairy, eggs Pies, pastries, cheese, sliced processed meats Custards, desserts, mayonnaise, salad dressings Fish/shellfish Soy products Potentially Hazardous Foods Cooked vegetables & starches Beans, rice, pasta, potatoes Raw seed spouts Alfalfa, mung bean Preserves Jams, jellies Garlic and herbal oils Food Service Establishments Sources of Foodborne Microorganisms: Humans: Nose & throat, hands, mucosal secretions, fecal matter, clothing, utensils Foods of animal origin: Poultry, meat, eggs, fish/shellfish Foods of plant origin: Soils, water Air and dust Hazard Analysis & Critical Control Points (HACCP) Principle 2: Determine the Critical Control Points A critical control point (CCP) is a point, step or procedure in the food manufacturing process at which a control measure can be applied and is essential to prevent, eliminate or reduce a food safety hazard to an acceptable level. Determining the CCPs involves identifying where in the processing operation the hazards addressed in the HACCP plan can be prevented, reduced or eliminated  Bacteria / Virus / Parasites in Food Served raw Insufficient Infected cooking workers, Dirty hands, Thorough UNSAFE Contaminated Cooking FOOD equipment / utensils SAFE Cooled rapidly to 40oF UNSAFE FOOD FOOD SAFE FOOD Held hot Served immediately 140oF Reheated rapidly to 165oF SAFE SAFE SAFE FOOD FOOD FOOD Hazard Analysis & Critical Control Points (HACCP) Principle 3: Establish Critical Limits Critical limits are criteria that separate safe product from unsafe product. Critical limits must be established for each CCP. Critical limits must be clearly defined and measurable Limit Time food is in Danger Zone o o o Between 40 F and 140 F (5 C and o 60 C) No more than a combined total of 4 hours for all procedures Thawing Preparation time Cooling Reheating Hazard Analysis & Critical Control Points (HACCP) Principle 4: Establish Monitoring Procedures Monitoring is the process of conducting a planned sequence of observations or measurements to determine if a CCP is under control. For each CCP, monitoring procedures must be implemented and documented to ensure that the critical limit is being met Hazard Analysis & Critical Control Points (HACCP) Principle 5: Establish Corrective Actions Corrective actions are predetermined activities that are taken when CCP monitoring results indicate that a deviation has occurred and there is the potential that unsafe food has been, or will be, produced. For each CCP there must be planned, written corrective actions. The objectives of taking corrective actions are to regain control of the hazard, to determine the disposition of the affected product and to prevent a reoccurrence of the problem Hazard Analysis & Critical Control Points (HACCP) Principle 6: Establish Verification Procedures Verification is the application of methods, procedures, tests and other evaluations, in addition to monitoring, to determine conformance with the HACCP plan. Verification confirms that the HACCP plan is operating effectively and according to written procedures Hazard Analysis & Critical Control Points (HACCP) Principle 7: Establish Record-Keeping and Documentation Procedures HACCP plans, including all of the items listed above, must be documented. The required monitoring and verification records must be complete and accurate Hazard Analysis & Critical Control Points (HACCP) SUMMARY Hazard of concern to food safety Unacceptable Contamination Microbial growth Survival of microorganisms Persistence of toxins Risk assessment: Probability that a condition will lead to a hazard Severity: Seriousness of the consequences resulting from a hazard Sprouted Seeds: Case Study increasing popularity in Canada favoured for their nutritional value linked to outbreaks of foodborne illness E.g. mung bean sprouts, alfalfa sprouts  Foodborne Outbreaks Associated with Seed Sprouts Year Seed Sprout Bacteria No. ill Location 1995-1999 alfalfa Salmonella >300 Canada-wide 2000 -2005 mung bean Salmonella >100 Canada-wide 1996 radish E. coli O157:H7 >6000 Japan 2011 fenugreek E. coli O104:H4 >9000 Germany Microbial Contamination of Sprouted Seeds Contamination most likely originated from seeds - usually for field planting & not for raw consumption - in the field or during harvesting, storage or transportation Germination process in sprout production involves keeping seeds warm and moist for 4 to 7 days low levels of microbial contaminants on seeds quickly reach levels high enough to cause illness CFIA Code of Practice for the Hygienic Production of Sprouted Seeds Code recommends control of pathogens to occur in two areas: during seed production and during sprout production Sprout manufacturers should control food hazards through a system based on Hazard Analysis and Critical Control Point (HACCP) principles A HACCP type program will reduce the risk of unsafe food by taking preventive measures to assure the safety and suitability of food at an appropriate stage in the operation by controlling food hazards http://www.inspection.gc.ca/english/fssa/frefra/safsal/sprointe.shtml#a1 Section 8. Control of Sprouting Operations Section 8.1 Control of food hazards Identify hazards that may be associated with sprouts and the sprouting process; Identify any steps in their operations which are critical to control the safety of sprouts; Implement effective control procedures at those steps by establishing critical limits; Monitor control procedures to ensure their continuing effectiveness; Have procedures in place for dealing with deviations that may occur with the critical limits; Verify control procedures periodically and whenever the operations change; and Maintain records as specified in section 9 of this Code Section 9: Documents and Records Written records that accurately reflect product information and operational controls should be available to demonstrate the adequacy of the manufacturing activities Records should: be available on demand be legible, permanent, accurate and be signed and dated by the individual(s) responsible include written procedures, controls, limits, monitoring results and subsequent follow-up documents Records must include: seed sources and lot numbers water analysis results sanitation checks pest control monitoring sprout lot codes sprout and spent irrigation water analysis results production volumes storage temperature monitoring product distribution any consumer complaints Records should be retained for at least 1 year for each lot of sprouts Listeria contamination of processed meat product Maple Leaf Foods, Aug 2008 Listeriosis outbreak 56 confirmed cases (41 in Ontario) 20 deaths Listeria: Foodborne bacteria that can grow at refrigerator temperatures Found in soil, water, decaying vegetation, and the intestinal tract of animals Infections results in flu-like illness, diarrhea or upset stomach Healthy individuals rarely seriously ill Listeria contamination of processed meat product Maple Leaf Foods, Aug 2008 Listeriosis can cause serious health problems even death in certain high-risk groups: Pregnant women and their unborn babies Newborns Elderly Individuals with weakened immune systems Infection may spread to the nervous system, with headache, stiff neck, confusion, loss of balance, or convulsions An infected pregnant mother may experience only a mild, flu-like illness, yet the infection can severely affect her unborn baby leading to miscarriage, premature labor, the delivery of a low-birthweight infant, and a wide range of health problems for a newborn or even infant death Listeria contamination of processed meat product Maple Leaf Foods, Aug 2008 Listeria cannot be completely eliminated from the environment important that surfaces in direct contact with product, such as slicers, must be 100% free of contamination contamination was most likely the result of a combination of factors, including: the potential for equipment to harbour organic material employee and product movement physical factors Listeria contamination of processed meat product Maple Leaf Foods, Aug 2008 CFIA response Investigation did not confirm the source of contamination Aware of potential contributing factor related to inadequately cleaned meat slicing equipment CFIA advice to all operators of federally registered establishments using meat slicing equipment is to use appropriate measures to address this potential risk factor Listeria contamination of processed meat product Maple Leaf Foods, Aug 2008 If warranted, and in consultation with the CFIA inspector: Review the standard cleaning and sanitation procedures for such equipment to ensure that internal working parts are being suitably cleaned and disinfected on an ongoing basis This includes the introduction of routine Listeria environmental sampling of contact surfaces for such equipment, if such testing is not already being done  Salmonella in chicken curry 250 sickened http://www.foodsafetynews.com/2015/03/foodborne-illness-in- australia-sickens-175-hospitalizes-24/#.VPh3zC50fYg “E. coli: More than 80% of cases were a result of eating beef and row crops such as leafy green vegetables” Salmonella: “77% of cases were related to eggs, chicken, beef, bean sprouts, pork and seeded fruits and vegetables such as melons and tomatoes” Listeria: “the report finds fruits such as cantaloupe accounted for about half of all listeria infections; dairy was to blame in about 31 percent of cases” http://www.cbsnews.com/news/biggest-culprits-of-foodborne- illness/