Monitoring Food Safety Module 1 Learning Objectives This module will introduce students to the varied factors contributing to food safety. As such students will receive an overview of the causes of food borne illnesses and contamination.
At the end of these lectures students should be able to… • Describe the agents responsible for food borne illnesses and contamination • Describe the functions of the agencies that oversee food safety regulations • Know how to report food borne diseases (locally and nationally) Goals
Food Safety by the Numbers How safe is our food - relative to other diseases?
Roughly 1 out of 6 Americans (or 48 million people) gets sick yearly • 128,000 are hospitalized • 3,000 die Estimates of Foodborne Illness in the United States
Number of deaths: 2,423,712 (2007) • Death rate: 803.6 deaths per 100,000 population • Life expectancy: 77.9 years • Infant Mortality rate: 6.75 deaths per 1,000 live births • Heart disease: 616,067 • Cancer: 562,875 • Stroke (cerebrovascular diseases): 135,952 • Chronic lower respiratory diseases: 127,924 • Accidents (unintentional injuries): 123,706 • Alzheimer's disease: 74,632 • Diabetes: 71,382 • Influenza and Pneumonia: 52,717 • Nephritis, nephrotic syndrome, and nephrosis: 46,448 • Septicemia: 34,828 Foodborne Illness: 3,000 (0.12% of all deaths) Active duty military deaths: 1,953 Lightening: 60 Number of Deaths for Leading Causes of Death
Pathogen Estimated number of illnesses % • Norovirus 5,461,731 58 • Salmonella, nontyphoidal 1,027,561 11 • Clostridium perfringens 965,958 10 • Campylobacter spp. 845,024 9 • Staphylococcus aureus 241,148 3 Top Five Pathogens Contributing to Domestically Acquired Foodborne Illnesses
Pathogen Est. number of deaths % • Salmonella 378 28 • Toxoplasma gondii 327 24 • Listeria 255 19 • Norovirus 149 11 • Campylobacter spp. 76 6 Top Five Pathogens Contributing to Domestically Acquired Foodborne Illnesses Resulting in Death (2007)
Causes of Illness in 1,565 Single Food Commodity Outbreaks, 2003–2008What Foods Pose the Greatest Risk?
Campylobacter (poultry) • E. coli O157 (ground beef, leafy greens, raw milk) • Listeria (deli meats, unpasteurized soft cheeses, produce) • Salmonella (eggs, poultry, meat, produce) • Vibrio (raw oysters) • Norovirus in many foods (e.g., sandwiches, salads) • Toxoplasma (meats) Germs (and some foods) Responsible for Most Foodborne Illness:
What You Can Do to Prevent Foodborne Illnesses CLEAN: Wash produce. Rinse fresh fruits and vegetables in running tap water to remove visible dirt and grime. Remove and discard the outermost leaves of a head of lettuce or cabbage. Because bacteria can grow well on the cut surface of fruit or vegetable, be careful not to contaminate these foods while slicing them up on the cutting board, and avoid leaving cut produce at room temperature for many hours. Changing a baby's diaper while preparing food is a bad idea that can easily spread illness!
What You Can Do to Prevent Foodborne Illnesses SEPARATE: Don't cross-contaminate one food with another. Avoid cross-contaminating foods by washing hands, utensils, and cutting boards after they have been in contact with raw meat or poultry and before they touch another food. Put cooked meat on a clean platter, rather back on one that held the raw meat.
What You Can Do to Prevent Foodborne Illnesses COOK: Thoroughly cook meat, eggs, and poultry. Using a thermometer to measure the internal temperature of meat is a good way to be sure that it is cooked sufficiently to kill bacteria. Ground beef should be cooked to an internal temperature of 160°F. Eggs should be cooked until the yolk is firm.
What You Can Do to Prevent Foodborne Illnesses CHILL: Refrigerate leftovers promptly. Bacteria can grow quickly at room temperature, so refrigerate leftover foods if they are not going to be eaten within 4 hours. Large volumes of food will cool more quickly if they are divided into several shallow containers for refrigeration.
What You Can Do to Prevent Foodborne Illnesses REPORT: Report suspected foodborne illnesses to your local health department. The local public health department is an important part of the food safety system. Often calls from concerned citizens are how outbreaks are first detected. If a public health official contacts you to find out more about an illness you had, your cooperation is important.
What You Can Do to Prevent Foodborne Illnesses http://chfs.ky.gov/dph/ REPORT TO YOUR LOCAL OFFICIALS!
http://www.foodsafety.gov/ Sources of Information
Challenges to food safety will continue to arise in unpredictable ways, largely due to: • Changes in our food production and supply • Changes in the environment leading to food contamination • Rising number of multistate outbreaks • New and emerging germs, toxins, and antibiotic resistance • New and different contaminated foods, such as prepackaged raw cookie dough, bagged spinach, and peanut butter, causing illness Current Food Safety Challenges
Food Contaminants Chemicals Lead, cadmium, mercury, nitrites, nitrates, organic compounds Biological agents Bacteria, viruses, molds - (or toxins of these); parasites, antibiotics Microbial sources account for 95% of all reported outbreaks or 97% of all cases
Burden of Disease Grossly underreported 325,000 hospitalizations in US; 5,000 deaths Actual number of cases > 70 million $23 billion in costs Outbreaks have decreased in recent years Not all diseases: post-diarrheal hemolytic uremic syndrome, E Coli O157-H7 Most cases of foodborne illness are sporadic and not connected with a specific outbreak
1900 • Botulism • Brucellosis • Cholera • Hepatitis • Scarlet fever (streptococcus) • Staphylococcal food poisoning • Tuberculosis • Typhoid fever • 1975-1995 • Norwalk-like viruses • Campylobacter jenjuni • Salmonella Enteritidis • Shiga toxin-producing E. coli O157:H7, • O111:NM, O104:H21 • Listeria monocytogenes • Clostridium botulinum (infant) • Vibrio cholerae 0139 • Vibrio vulnificus • Yersinia enterocolitica • Arcobacterbutzleri • Hepatitis E • Cryptosporidium parvum • Giardia lamblia • Cyclosporacayetanensis • Toxoplasma gondii • BSE prion • Nitzchiapungens (dinoflagellate) Emergence of Foodborne Pathogens
Norwalk-like virus Campylobacter Salmonella C. perfringens Giardia S. aureus 0 2,000,000 4,000,000 6,000,000 8,000,000 10,000,000 Most Common Causes of Foodborne IllnessMead et al, 1999
Major Foodborne Infections, 1997-2003 Rate per 100,000 population Campylobactor species 2010 Targets Salmonella species Listeria monocytogenes Escherichia coli O157:H7 HUS* Note: 2003 data are preliminary. *New measure for postdiarrheal hemolytic uremic syndrome (HUS) for children under 5 years; target to be determined. Source: Foodborne Disease Active Surveillance Network (FoodNet), CDC, FDA, USDA, and State agencies.
Norwalk-like Viruses 23 million cases annually; 50,000 hospitalized; 30 deaths Fecally contaminated food: salads, sandwiches, fruit, improperly cooked shellfish; P-T-P transmission Extremely contagious Low dose to cause infection Infectious for 2 weeks after recovery Cruise ships Control problem: lack of simple/sensitive technique for detecting presence
Hepatitis A Infectious agent present in feces Most frequently occurs in school-age children Common sources are foods that are not cooked or foods that are handled after cooking by infected handlers Raw/undercooked mollusks from contaminated waters Contaminated produce, e.g. lettuce, strawberries Common childhood disease in developing world
Hepatitis A (continued) No chronic form. < 1/100 mortality rate Vaccine nearly 100% protective One dose: 3 years protection. With booster at 6-12 months: lifetime protection Amer Academy of Pediatrics: Rec. vaccine @ age 1 Wikipedia: “Chi-Chi's was a popular Mexican restaurant chain from 1975 to 2004. It went out of business in the United States following a 2003 hepatitis A outbreak that began at one of their locations outside of Pittsburgh, PA.” Green onions from Mexico
Campylobacter jejuni One of most common bacterial causes of diarrhea 15/100,000 diagnosed; underreported: > 1 million; 100 fatalities Isolated, sporadic events not outbreaks Diarrhea, N/V - 2 to 5 d after ingestion Spiral shaped bacteria Grows best at bird’s body temperature; can’t tolerate drying or low O2 Chicken flocks are silently infected and bacteria spreads easily through water or fecal contact When infected bird is slaughtered, bacteria is transferred from intestines to meat. Also in giblets esp. liver >50% of raw chicken in US has C. jejuni on it
Vibrio parahaemolyticus Same family as cholera Lives in brackish saltwater (halophilic) - naturally inhabits coastal waters in US D/N/V/F/C within 24 hrs. Self-limited - 3 d. Severe disease in immune compromised Most infections from eating raw or undercooked shellfish, especially oysters Can cause skin infection in open wound exposure to seawater Incidence (diagnosed): 0.25/100,000 (Food Net)
Shigella Group of bacteria S. sonnei: 2/3 of US cases; S. flexneri: 1/3 cases; S.dysenteriae: deadly epidemics in developing world 18,000 reported cases. Actual number: 20X. Sweeps through communities; recurrence in poor hygiene settings; summer>winter; toddlers (2 - 4 yrs); spreads through daycare setting then to families P-T-P transmission. Fecal-oral transmission. Infectious period during sickness and for 1 - 2 weeks after. Infxn from eating contaminated food: infected handlers; vegetables contaminated with sewage; flies breed in infected feces and then contaminate food; also drinking or swimming in contaminated water
Shigella (contimued) F/D (bloody), cramps: 1 to 2 d after exposure. Resolves in 5 - 7 d but can be severe in old and young. Febrile seizures in children Treat with antibiotics: kills bacteria in stools and shortens illness Some resistance to antibiotics and use may create more resistance. When many in community are affected, antibiotics used selectively to treat only severe cases since mild infections usually clear
MMWR WeeklyOctober 6, 2006 / 55(39) 1068 - 1071 Outbreaks of Multidrug-Resistant Shigella sonnei Gastroenteritis Associated with Day Care Centers --- Kansas, Kentucky, and Missouri, 2005 Kentucky. During May 1--August 31, 2005, a total of 148 confirmed cases of S. sonnei infection were reported in Fayette County which represented a 42-fold increase above the previous 5-year baseline. The median age of patients was 4 years (range: 0--61 years); among children aged <10 years, 59 (50%) were female. Among adults aged >18 years, 18 (78%) were female. A total of 137 (93%) cases occurred among attendees, their family members, or staff at 16 day care centers in Fayette County. Twelve isolates underwent antimicrobial susceptibility testing at the University of Kentucky; all were resistant to ampicillin and TMP/SMX, and none were resistant to ceftriaxone or ciprofloxacin.
Listeria monocytogenes In soil and water. Vegetable contamination from soil or manure Animals carriers without appearing ill Uncooked meats/vegetables; contamination after processing or cooking (e.g. soft cheese, cold cuts); unpasteurized milk Advanced age, pregnant women, newborns, immune compromised Miscarriage, stillbirth, premature, infxn in newborn Fever, muscle aches, GI. If CNS spread, headache, ataxia, convulsion 2,500 cases / year with 500 deaths Some deaths even with early antibiotic treatment
Yersiniaenterocolitica Rod-shaped bacteria Major animal reservoir: pigs Bacteria most likely found on pig tonsils Infections from raw/undercooked pork (chitterlings); unpasteurized milk Most often young children Fever, abdominal pain, bloody diarrhea Confused with appendicitis 1/100,000 culture confirmed infections / year
Salmonella Many strains: S. typhi (typhoid); S. typhimurium(salmonellosis); S. enteritidis(eggs) Flagellated, gram negative 40,000 reported cases/year. Actual: 30X. 600 deaths F/D, cramps 12 to 72 hrs after infxn. Duration 4 to 7 d. Most recover without treatment. Some may need hospitalization from dehydration or spread to blood. **May be several months before bowel habits entirely normal Small number develop Reiter’s syndrome: joint pain, eye irritation, painful urination. Can last months or years and can lead to chronic arthritis
Salmonella (continued) Antibiotic treatment if spread of infection from intestines. Some antibiotic resistance due to use of antibiotics to promote the growth of feed animals Fecal - oral (animals & humans). Live in intestinal tracts. Infection commonly from food contaminated with animal feces Reptiles particularly likely to harbor infxn (pet turtles!) Contaminated food often of animal origin but all foods at risk. Avoid raw eggs, unpasteurized milk Thorough cooking kills bacteria Food handlers can transmit.
Eggs: Salmonella enteritidis Past decades: fecal contamination of shell 1970’s: stringent cleaning and inspection Recent years: intact / disinfected eggs Silent infection of hens ovaries - appear healthy Eggs contaminated before shells formed Small # hens infected at any given time. Infected hen lays many normal eggs with only occasional contaminated one 1/10,000 eggs internally contaminated (NE US)
Investigation Update: Outbreak of Salmonella Typhimurium Infections, 2008–2009 Update for March 17, 2009 The numbers of new cases have declined substantially since the peak in December, but illnesses are still being reported among people who ate the recalled brands of peanut butter crackers after the recall. The outbreak is expected to continue at a low level for the next several months since consumers unaware that they have recalled products in their home continue to consume these products, many of which have a long shelf-life. Consumers should avoid eating recalled products. Case count is 691 in 46 states with latest confirmed, most recent reported illness beginning on February 24, 2009. Major national brands of jarred peanut butter found in grocery stores are NOT on the Peanut Corporation of America recall list.
Parasites Entamoeba histolytica “amebiasis” Developing world Fecal - oral: ingestion of cysts (eggs) 1 - 4 weeks incubation 1/10 get sick, usually mild symptoms Uncommon spread to lungs, liver, brain Giardia lamblia Every region of US: drinking and recreational waters In intestines of infected animals/humans. Fecal - oral. PTP and contaminated food. Prolonged survival outside the body & in environment 1 - 2 weeks incubation; 2 - 6 weeks symptoms
Parasites Cyclospora One-celled parasite - submicroscopic 1st human case in 1979, more in mid-80’s. Now, US outbreaks Stool-contaminated food / water, e.g. fresh produce. Requires days to weeks after passed in stool to become infectious So, probably not PTP direct transmission Week incubation. Symptoms from days to > 1month; relapse Cryptosporidium One of most common causes of waterborne disease in US. Found in every region Parasite lives in intestine. Millions of parasites in stool Protective outer shell - can survive outside body for long periods and resistant to chlorine-based disinfectants 2 - 10 d incubation. Symptoms for 1 - 2 weeks; cycles