FDSC3940: Spoilage fungi, gram negative bacteria, and lactic acid bacteria

prevent fungal spoilage

filter air and water, thermal treatment, protective cultures, vacuum or modified packaging

gram negative

spoilage bacteria are gram negative

undesirable in food

sources of gram negative bacteria

raw ingredients, water, footwear, hands

coliforms

gram negative rods that can ferment lactose

in Enterobacteriaceae family

produce heat-stable lipase and protease that cause bitterness and rancidity

coliform defect

bacterial soft rot caused by pectobacterium carotovorium

ropy milk

cheese early blowing

Pseudomonas

found in almost every environment on earth, can possess enzymes to break down almost any nutrient source

this break down leads to off flavors, odors, and textures

lactic acid bacteria

gram positive rods that produce lactic acid bacteria

fermentation

culture added to product intentionally

spoilage

introduced to the product unintentionally

slimy milk

Leuconostoc spoilage of fluid milk, large amounts of polysaccharides