Madison Chemical Food Division Microbiology Terry Willis-Senior Advisor-Food Division

What is Microbiology? Micro=microscopic / Biology=study of life So it is the study of microorganisms. Microorganisms are single cell organisms and the smallest form of life that are present everywhere in our environment. 1 bacterial organism can multiply to over 2 million in 7 hours under the right environmental conditions. In food processing, microorganisms play major roles in processing, preservation, spoilage, and food-borne illness.

5 Basic Groups Bacteria Mold Yeast Viruses Protozoans

Good Microorganisms Some microorganisms are used in food processing to produce the final cultured product. Buttermilk Sour Cream Cheese Yogurt Sauerkraut Pickles Soy Sauce Sausage

Harmful Microorganisms Harmful organisms can cause product spoilage or can be pathogens to humans. Some Typical Spoilage Organisms: Pseudomonas Bacillus Penicillium Lactobacillus Rhodotorula Cladosporium

Harmful Microorganisms (Cont.) Cause illness in humans Mostly gastrointestinal Mainly affects young, elderly and immunocompromised Examples are: Salmonella Campylobacter Listeria Cyclospora E. Coli Shigella

Factors Affecting Microbial Growth Food Temperature Moisture pH Oxygen Time

Factor - Food Like all living organisms, bacteria need food to grow: Insoluble Organics Protein Carbohydrates Fats and Oils

Factor - Temperature Temperature controls the growth rate. Bacteria have minimum, optimum and maximum temperatures for growth. Freezing does not kill bacteria. Heating can kill most cells but not all spores.

Factor – Temperature (Cont.) Growth Ranges Psychrotrophs 32°F – 85°F Mesophiles 75°F – 115°F Thermophiles 114°F – Higher Thermoduric Able to survive pasteurization

Factor - Moisture All microorganisms require water. Very low water availability (Such as peanut butter, cereal, dried fruit) They die or become dormant. Spoilage of a product mainly depends on available water content.

Factor - pH Common Foods Disease causing bacteria will not grow below pH 4.6 (example: Listeria and Salmonella) Not necessarily true of spoilage organisms (example: Lactobacillus) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Acid Neutral Alkaline Tomatoes 4.2 4.6 Raw Meat 5.8 Egg Yolk 6.4 Egg White 8.0

Factor - Oxygen 2 types bacteria classifications Aerobic – bacteria that thrive in presence of oxygen Anaerobic – bacteria that thrive where there is no oxygen Canned goods Vacuum packages Modified Atmospheric Packages (MAP) Products heated for long periods of time

Factor - Time There are four life stages of bacteria and each moves through those stages at varying speed, depending upon the proper combination of food, temperature, moisture, pH and oxygen. # Bacteria Time lag log stationary death

Biofilm Bio=life / Film=layer - so it is a layer of life These are communities of bacterial cells that adhere to surfaces and each other. They secrete a glue-like material called polysaccharide that holds them together and protects them. The bacteria will continue to multiply within this protective layer to a point that it cannot contain all the organisms and equipment/product contamination occurs. Sporadic high swab counts can be an indicator of a biofilm problem.

Biofilm Growth and constant contamination source.

Biofilm Free-floating (planktonic) bacteria that are not attached to surfaces and protected are easier to remove and to eliminate with sanitizers. Chemicals and sanitizers cannot penetrate the polysaccharide film to kill the bacteria. Planktonic but will soon attach Polysaccharide

Biofilm Practices that may enhance formation: Short cuts in proper cleaning procedures Proper cleaning and preventative measures must include a balance of the proper chemical, time, temperature, concentration and application (physical action). Proper sanitizing as well as the proper type sanitizer are critical Equipment design can greatly affect the formation of biofilms if there are areas that are difficult to clean or areas that tend to pool soil, water, etc. Worn equipment as well as improperly repaired equipment. Things like rough welds, gaps in seams, cracked surfaces, rivets, etc.

Biofilm Practices that may enhance formation (cont.): Areas that may not be cleaned daily such as walls, floors, drains, etc. can tend to provide quicker biofilm formation because bacteria and soil are not thoroughly removed thus the bacteria grow and start forming the polysaccharide film quickly. Longer processing times have forced shorter cleaning times (often 4 hours or less), therefore less scrubbing can be done. CIP systems are less prone to biofilm because the turbulence acts as a scrubbing mechanism. Areas that can be biofilm problems in CIP are dead spaces or low flow areas. Extended processing times also extend times between cleanup (processing for 4-5 shifts allowing cleanup only every day and a half or even more).

Control Measures Raw Materials Set micro standards for raw materials and check incoming product. Inspect suppliers occasionally. Properly store ingredients Coolers, freezers or dry storage Quickly rotate ingredients “First In, First Out” Proper separation of ingredients “Like with like”

Control Measures Processing Use proper parameters Heat inactivation Time / temperature relationship Storage temperature

Control Measures Employees Proper personal hygiene Utilize Good Manufacturing Practices (GMPs) Effective Sanitation Cleaning and Sanitizing Proper Maintenance of Equipment Repair cracks and improper welds Replace worn or torn seals and gaskets