Food Preservation and Spoilage Flashcards
Food spoilage results from…
The growth of microbes in food which alter the food visibility and renders it unsuitable for consumption
Microbial growth is controlled by… (2)
- Intrinsic Factors
2. Extrinsic Factors
Factors that are related to the food itself
Intrinsic Factors
Factors that are effected by the environment in which they are stored
Extrinsic Factors
Intrinsic factors for carbohydrates
- Mold predominates
- Degrades food by hydrolysis
- Little odor
- Ergotism
What is ergotism?
- Hallucinogenic alkaloids released by Claviceps purpurea
- May cause death
Intrinsic Factors of Fats and Proteins. What dominates?
-Bacterial growth predominates
-
What are the 3 types of Bacterial growth in Proteins or Fats?
- Putrefaction
- Unpasteurized Milk Spoilage
- Butter
- Proteolysis and anaerobic breakdown of proteins
- Foul smelling amine compounds
Putrefaction
Acid production followed by putrefaction
Unpasteurized milk spoilage
Short chained fatty acid production
Ex. Rancid Butter
Butter
What are other intrinsic factors?
- pH
- Water availability
- Physical Structure
- Impacts make up of microbial community and therefore types of chemical reactions that occur when microbes grow in food
- Ex. Low levels of this favor yeast and mold
pH
Lower water activity (promotes/inhibits) microbial growth?
Inhibits
Grinding, mixing, and distributing of microbes (promotes/inhibits) microbial growth?
Promotes
The outer skin of fruits and vegetables (promotes/inhibits) microbial growth?
Inhibits
What are examples of antimicrobial substances? (5)
- Coumarins
- Lysozyme
- Aldehydic and phenolic compounds
- Allicin
- Polyphenols
Examples of extrinsic factors (3)
- Temperature
- Relative humidity
- Atmosphere
Temperatures effect on growth…
Lower temperatures retard microbial growth
Relative humidity effect on growth…
Higher relative humidity promote microbial growth
How does the atmosphere effect growth…
-Oxygen promotes growth
Use of shrink wrap and vacuum technologies to package food in controlled atmospheres
Modified Atmosphere Packaging
Methods for controlling Food Spoilage (6)
- Filtration
- Low Temperature
- Pasteurization
- Water Availability
- Chemical based preservation
- Radiation
What is the goal of preservation?
To eliminate or reduce the populations of spoilage and disease causing microbes while maintaining food quality
Refrigeration’s effect on growth?
5 degrees retards but does not stop microbial growth, microorganisms can still cause spoilage with extended storage
- This method kills most human pathogens and substantially reduces the number of spoilage of organisms
- Shorter heating times results in improved flavor
Pasteurization
Type of chemical based preservation
- GRAS “Generally recognized as safe”
- agents include organic acids, sulfite, ethylene oxide gas, ethyl formate, sodium nitrate
Use of ionizing radiation (gamma radiation) to extend shelf life of sterilized meat, seafoods, fruits, and veggies
-excellent penetrating power
Radiation
2 major types of Food Borne Diseases
- Food born infections
2. Food intoxications
How are food borne diseases transmitted?
- Breakdown in hygiene
- Fecal-oral route is key
- Fomites also important
Life pathway of food borne diseases (4)
- Ingestion of pathogen
- Growth of pathogen
- Tissue invasion
- Release of toxins
Characteristics of food borne intoxications
- Ingestion of food in which microbe have been growing
2. Produce symptoms shortly after the food has been consumed
Enterohemorrhagic E. coli disease characteristics
- Normal inhabitant of the intestines
2. Contamination of meat during slaughter
