3. Food Production, Security and Preservation

• Food microbiology


  A critical field that examines the microorganisms affecting food quality and safety
• Many modern preservation methods have their roots in ancient practices, discovered largely by chance
• These early discoveries laid the foundation for today's food preservation techniques, highlighting the interplay between tradition and scientific advancement
• Ancient food preservation methods

  • Dry Grains: Avoided mold growth
  • Soured Milk: Prevented further decomposition and remained palatable
  • Cheesemaking: Pressing curd, removing moisture, and ripening improved preservation and taste
  • Fermentation: Made certain plants like olives and cocoa more palatable
  • Dried Meat and Salted Fish: Resisted decay
• Sun Drying


  Oldest method of preservation, items were left in the sunshine to dry
• Jam


  Greeks and Romans used honey to preserve food, traders created jam to utilize rotting fruit
• Curing


  Storing food in salt solution (brine) discovered, meat was preserved in brine
• Refrigeration


  Freezing and refrigeration technologies developed, ancient communities preserved food under ice or in winter
• Canning


  Started by a French scientist known as Nicolas Appert, involves the storing of food in sterilized containers
• Pasteurization


  Invented by Louis Pasteur, identified relationship between microorganisms and food spoilage
• Dehydration


  Improved method of sun drying using electrical energy, popular among soldiers in World War II for light, dried foods
• Vacuum Packaging


  Invented by Karl Busch, removes oxygen from bags containing food to prevent bacterial growth
• Irradiation


  Based on the discovery of x-rays by Wilhelm von Roentgen, used in food preservation
• Chemical Preservatives


  Uses additives like vinegar to kill bacteria and inhibit enzyme activity, prehistoric methods included smoking and soaking meat in water
• HACCP system


  An essential tool for preventing food contamination, developed by the FDA and USDA
• HACCP system

  • Identifies where foods are most likely to be contaminated
  • Prevents introduction and proliferation of harmful microbes
  • FDA and USDA inspectors monitor ports and processing locations
  • Ensures adequate temperatures during processing and storage to kill pathogens
  • Methods like canning, drying, and refrigeration prevent spoilage and pathogen growth
• Food security


  The measure of an individual's ability to access food that is nutritious and sufficient in quantity, may also specify that food must meet an individual's food preferences and dietary needs for active and healthy lifestyles
• Industrial canning

  Industrially canned goods undergo commercial sterilization using steam under pressure in a large retort, similar to an autoclave, to destroy C. botulinum endospores and eliminate significant spoilage and pathogenic bacteria, but thermophilic bacteria can survive and cause spoilage at high temperatures, and underprocessing or leaking cans can lead to spoilage by mesophilic bacteria
• Aseptic packaging

  On the rise for materials like laminated paper or plastic that can't handle heat, continuous rolls are sterilized with hot hydrogen peroxide and UV light, while metal containers use superheated steam, high-energy electron beams also sterilize packaging, in a sterile environment the packaging is formed, filled with heat-sterilized liquid foods, and sealed without further sterilization
• Radiation and industrial food preservation

  Ionizing irradiation using X-rays, gamma rays, or high-energy electrons inhibits DNA synthesis, preventing microorganisms, insects, and plants from reproducing, it inactivates organisms without making food or packaging radioactive, low doses (<1 kGy) kill insects and inhibit sprouting, medium doses (1-10 kGy) pasteurize meats and poultry, and high doses (>10 kGy) sterilize spices by drastically reducing bacterial populations
• High pressure food preservation


  Preserves food by submerging prewrapped items like fruits, deli meats, and chicken strips in tanks of water under extreme pressure (up to 87,000 psi), this pressure disrupts bacterial functions, killing pathogens like Salmonella and E. coli, as well as nonpathogenic microorganisms, extending shelf life, pascalization preserves food color and taste without additives or regulatory approval
• Nineteenth century discoveries

  • Pure cultures of microbes were grown for food production
  • Understanding developed of the positive role of microbes beyond food spoilage
• Microbial action in cheese production

  Essential in curd formation and ripening
• Cheese types by hardness

  • Hard Cheese - Cheddar, Swiss
  • Semi-soft Cheese - Limburger, Blue, Roquefort
  • Soft Cheese - Camember
• Dairy products

  • Butter: Churning cream, flavor from diacetyls (from lactic acid bacteria fermentation)
  • Buttermilk: By-product of butter, also made by inoculating skim milk with bacteria
  • Sour Cream: Cream inoculated with similar bacteria as buttermilk
• Fermented milk beverages


  • Kefir and Kumis: 1-2% alcohol, with lactic acid bacteria and yeast
  • Yogurt: Milk thickened, inoculated with Streptococcus thermophilus and Lactobacillus delbrueckii bulgaricus, fermented at 45°C
• Non-dairy fermentation products

  • Cacao Beans: Microbial fermentation produces chocolate flavor
  • Bread: Yeast (Saccharomyces cerevisiae) ferments sugars
  • Sauerkraut, Pickles, Coffee, Olives, and Salami
• Alcoholic beverages and vinegar

  • Beer: Grain starches fermented by yeast, Lager: Slow fermentation with bottom yeasts, Ale: Fast fermentation with top yeasts, Sake: Rice wine using Aspergillus mold
  • Wine: Fermentation of grapes, malolactic fermentation by lactic acid bacteria to reduce acidity
  • Vinegar: Ethanol in wine converted to acetic acid by aerobic bacteria