The document discusses different types of microorganisms that can be found on foods, including bacteria, molds, and yeasts. It describes their structures, modes of reproduction, and optimal temperature and moisture conditions for growth. Several pathogens that can cause foodborne illness are also identified. Food preservation aims to prevent spoilage and ensure safety by controlling factors like pH, water activity, temperature, and oxygen levels that influence microbial growth.

1. Microbiological Principles of Food Preservation

18. Growth of Microorganisms

23. Budding

31. pH Ranges for Food pH 7.0 Neutral pH 0 pH 14 pH 2 pH 3.5 pH 9 pH 4.6 pH 5.5 pH 10 Limes Fruits & Berries Veggies Melons Meats, Milk Bleach Solutions Bacteria Grow

32. Comparison of Growth Requirements Organism pH Range Water Activity Requires Oxygen? Bacteria 4.4 to 9.8 Aw>0.85 Some- It Varies Yeasts 1 to 11 Aw>0.60 Not Usually Molds 1-12 Aw>0.60 Yes

33. Temperature of Growth Classification psychrotroph

34. Classification Optimum Temperature Psychrotroph Mesophiles Thermophiles 58ºF to 68ºF (14ºC to 20ºC) 86ºF to 98ºF (30ºC to 37ºC) 122ºF to 150ºF (50ºC to 66ºC)

38. Vegetative Cell Vegetative Cell with Spore Spore 3 Microscopic Forms of a Sporeformer Sensitive Resistant