1. ENVR 191 Food Safety and Foodborne Disease Lecture 1 December 3, 1999 Mark D. Sobsey

2. Sources of Foodborne Enteric Microbial Contamination Food handler ‑ associated contamination – Inadequate personal hygiene  fecal contamination of foods (e.g., hands) Food processing – Equipment, packaging and personnel contaminate foods during processing Food Storage: time and temperature abuse  bacterial growth Fecal contamination prior to harvest or collection – Animal foods contaminated naturally by infection (e.g., salmonella) – Surface contamination (e.g., feces on fur, feathers, hooves, etc.) – Shellfish and other fish contaminated in their environment Fecal (sewage) contamination of water  pathogen uptake by filter ‑ feeding on waterborne particles – Fish and shellfish naturally colonized by aquatic pathogens Vibrio cholerae in copepods, fish and shellfish – Produce contaminated by irrigation with sewage or contaminated water or fertilization with nightsoil (feces) or animal feces. – Soil contaminating plants and animals with bacteria, fungi, etc.

3. Foods Implicated in Foodborne Illness: Meats Red Meats – High contamination in comminuted and processed meats (e.g., ground beef, sausage) – High surface area, increased contact with processing equipment; increased handling; variety of sources from the animal (organs, trimmings, etc.). » Ex., E. coli O157:H7 outbreaks due to undercooked hamburger Poultry – High contamination levels in cut ‑ up poultry Increased handling, processing and contact with common equipment Salmonella and campylobacters are prevalent in some poultry flocks – can contaminate an entire processing plant via equipment and process baths (e.g., chiller tank) – Eggs Endogenous contamination by Salmonella enteritidis in some flocks – Time and temperature abuse leads to proliferation in the egg » Raw/undercooked eggs a source of exposure and infection

4. Foods Implicated in Foodborne Illness: Fish Contamination depends on type of seafood,quality of harvest water and amount of processing, handling and storage. Bivalve mollusks (oysters, clams, mussels, etc.); filter feeders – Accumulate enteric pathogens from fecally contaminated waters – Acquire high levels of vibrios from their environmental waters Crustaceans (e.g., crabs) – Acquire some pathogens by feeding on mollusks – Acquire high levels of vibrios from their water environment Vibrio levels can increase during handling, processing and storage, especially if temperatures are too high. Fin fish – Outer surface and epithelial lining (e.g., gut) contamination by enteric microbes in fecally contaminated waters; – Contamination during processing (e.g., filleting). – Endogenous contamination: Ex:: Diphyllobothrium latum ; fish tapeworm; anemia; undercooking

5. Other Foods Implicated in Foodborne Illness Produce (fruits and vegetables) – fecal contamination in irrigation water and other fecal sources (animal droppings, birds, etc.) – inadequate or unsanitary picking, washing or processing. Dairy Products – In developed countries milk and related dairy products are usually made from pasteurized milk. Raw milk and products (e.g., cheeses) made from unpasteurized milk are high risk of bacteria contamination – salmonella, campylobacter, brucella, yersinia, listeria,). Unpasteurized fruit juices and other beverages – fecal contamination from animal and human sources Deli, "Fast" and Restaurant Foods – salads, sandwiches, other fast, deli or restaurant foods – become fecally contaminated during preparation and handling Cereal and Grain: inadequate storage of cooked rice/grain

6. Methods to Control Fecal Contamination of Foods - I Prevent exposure to fecal contamination in the environment, after harvest or during processing, preparation and handling Maintain sanitation in the environment: – harvest shellfish only from waters that are not fecally contaminated; – irrigate fruits and vegetables with non ‑ fecally contaminated water. – fertilize fruits and vegetables with uncontaminated fertilizers. Maintain uninfected herds and flocks of animals – Immunize animals against infectious diseases: Brucella abortus : brucellosis from cattle; raw milk/dairy products – Colonize animals with harmless microflora: Colonize baby chicks with harmless bacteria competitive to Salmonella – Destroy animals harboring pathogens: Bovine Spongiform Encephalopathy (BSE; “mad cow” disease); – Caused by a prion able to infect humans (neural tissue in meat)

7. Methods to Control Fecal Contamination of Foods - II Maintain adequate hygiene and sanitation during harvest, processing, storage and distribution. Source control: use of non ‑ fecally contaminated foods and ingredients; Use clean water for washing, processing, cleaning and worker hygiene; Adequate human and food waste treatment and disposal facilities Plant and equipment sanitation: clean, sanitize, etc. Personal hygiene, food handling practices and employee health (education, training and policies). Criteria and standards and guidelines for fecal contamination (pathogens and microbial indicators). Inspection, monitoring and surveillance (product testing)