Food And Feed Preservation - Overview

The microorganisms related to food & feed safety, preservation, and fermentation processes. Basics about those MO and information on quality and microbiological safety, the role of lactic acid bacteria, protective cultures...The fundamental aspects of the biologically viable methods for food and feed preservation.

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Flashcards	80
Language	English
Category	Biology
Level	University
Created / Updated	15.05.2022 / 22.05.2022
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Lactococcus 1

nonmotile, sensitive to antibiotics

partially motile, sensitive to antibiotics

catalase and oxidase(-), incapable of reducing nitrate

catalase and oxidase(+), incapable of reducing nitrate

catalase and oxidase(+), capable of reducing nitrate

Lactococcus 2

facultative anaerobes, mesophiles, lactic acid homoformentation

facultative aerobes, mesophiles, lactic acid homoformentation

facultative aerobes, thermophiles, lactic acid homoformentation

facultative aerobes, thermophiles, lactic acid heteroformentation

facultative anaerobes, mesophiles, lactic acid heteroformentation

Lactococcus 3

found in milk, on green parts of plants

production of bacteriocins: Nizin

production of bacteriocins: Nitamycin

found in ruminant digestive system

found on the animal and human skin and mucous membranes, in water, soil, air, food

Lactococci used in food production:

L. lactis ssp. lactis

L. lactis ssp. cremoris

L. lactis ssp. cremosa

L. lactis ssp. lacta

L. lacti ssp. lactis

Enterococcus 1

nonmotile, resistant to antibiotics

partially motile, resistant to antibiotics

nonmotile, sensitive to antibiotics

catalase and oxidase(-), incapable of reducing nitrate

catalase and oxidase(+), incapable of reducing nitrate

Enterococcus 2

facultative anaerobes, mesophiles, lactic acid homofermentation

found in the animal and human digestive system

Resistant to high concentrations of NaCl

found in milk, on green parts of plants

facultative anaerobes, mesophiles, lactic acid heterofermentation

Enterococcus 3

thermoduric bacteria which can survive, to varying extents, the pasteurisation process

survive freezing process

do not survive freezing process

psychotroph bacteria which can survive, to varying extents, the pasteurisation process

psychoduric bacteria which can survive, to varying extents, the pasteurisation process

Enterococcus 4

Enterococci are resistant to preservatives

Enterococci are resistant to antibiotics

Enterococci are resistant to desinfectants

Enterococci exhibit amino acid decarboxylating activity – biogenic amines (histamine)

Enterococci exhibit weak proteolytic properties - some couse sweet curdling of milk

Enterococcus 5

possible transfer of antibiotic resistance genes

not allowed to be used in food production

allowed to be used in feed production

allowed to be used in food production

not allowed to be used in feed production

Leuconostoc 1

nonmotile, sensitive to antibiotics

nonmotile, resistant to antibiotics

catalase and oxidase(-), incapable of reducing nitrate

catalase and oxidase(+), incapable of reducing nitrate

catalase and oxidase(-), capable of reducing nitrate

Leuconostoc 2

facultative anaerobes, mesophiles, lactic acid heteroformentation

facultative aerobes, mesophiles, lactic acid homoformentation

facultative anaerobes, termoophiles, lactic acid heteroformentation

found in milk, on green parts of plants

found in the animal and human digestive system

Leuconostoc 3

used in production of dextran - produced in the glycocalyx covering the cells (synthetic blood plasma substitute, slime defects in food products)

capable of performing citrate fermentation (diacetyl - butter flavor)

cause flavor defect in the brewing industry

amino acid decarboxylating activity – biogenic amines (histamine)

resistant to high concentrations of NaCl

Pediococcus 1

occur in pairs or tetrads, nonmotile, senstitive to antibiotics

occur in triads or tetrads, motile, senstitive to antibiotics

occur in pairs or triads, nonmotile, resistant to antibiotics

catalase and oxidase(-), incapable of reducing nitrate

catalase and oxidase(+), capable of reducing nitrate

Pediococcus 2

facultative anaerobes, mesophiles, lactic acid homoformentation

facultative aerobes, thermophiles, lactic acid homoformentation

found in meat, green parts of plants

found in milk, green parts of plants

obligate anaerobes, mesophiles, lactic acid heteroformentation

Which of these Pediococci are used in starter cultures in the meat industry?

P. acidilactici

P. pentosaceus

P. pentosauce

P. acidilactococci

P. pentose

Lactobacillus 1

short or long rods, sensitive to antibiotics

catalase(-), incapable of reducing nitrate, high nutritional requirements

catalase(+), capable of reducing nitrate, high nutritional requirements

oxidase(+), short or long rods, resistant to antibiotics

catalase and oxidase(+), capable of reducing nitrate, low nutritional requirements

Lactobacillus 2

facultutive anaerobes or microaerophiles, mesophiles and thermophiles

facultutive aerobes or microaerophiles, thermophiles

obligate anaerobes or microaerophiles, mesophiles

found on mucous membranes, digestive system, plant material, milk, meat

found in meat, green parts of plants

Lactobacillus 3

lactic acid homofermentation

lactic acid heterofermentation

may cause spoilage defects – color defects in meat e.g. greening

some probiotic bacteria

starter culture component in meat industry

Lactobacilli exhibit antimicrobial activity through the following metabolites:

lactic acid

acetic acid

H2O2

bacteriocins

butyric acid

Propionibacterium 1

pleomorphism (X, Y, coccoid), facultative anaerobes, catalase(+), incapable of reducing nitrate

pleomorphism (X, Y, bacilloid), facultative aerobes, catalase(+), incapable of reducing nitrate

pleomorphism (X, Y, bacilloid or coccoid), facultative anaerobes, catalase(-), capable of reducing nitrate

found in rumen of cattle and sheep

found on mucous membranes, digestive system, plan material, milk, meat

Propionibacterium 2

propionic acid fermentation: propionic acid, acetic acid, CO2

propionic acid fermentation: propionic acid, butyric acid, CO2

synthesis of vitamin B12

antimicrobial metabolites

some are probiotic

Bacillus 1

aerobes and facultative anaerobic bacteria, catalase (+)

anaerobes and facultative anaerobic bacteria, catalase (-)

facultutive anaerobes or microaerophiles, catalase (+)

found in soil, air, raw materials, water

found on mucous membranes, digestive system, plant material, milk, meat

Bacillus 2

heat-resistant spores: efficiency of thermal processes

capable of: reduction of nitrates

capable of: producing antimicrobial metabolites (lactic acid, acetic acid, H2O2, bacteriocins)

capable of: breakdown sugars (oxidation)

capable of: hydrolysis of proteins and lipids

Bacillus 3

food spoilage: souring of canned meat and fish

food spoilage: souring of cheese

food spoilage: color defects in meat e.g. greening

food spoilage: color defects of canned meat and fish

food spoilage: color defects of dairy product

Pathogenic Bacillus species:

B. cereus (exotoxins)

B. anthracis (anthrax - biological weapon)

B. subtilis (exotoxins)

B. coagulans (endotoxins)

B. antraxis (anthrax - biological weapon)

Commercial-scale production of Bacillus for production of:

enzymes (amylases), antibiotics, insecticides

vitamins, hyaluronic acid, polygalacturonic acid

probiotic additives

polygalacturonic acid, acetic acid

hyaluronic acid, acetic acid

Saccharomyces sp .:

alcoholic fermentation in winemaking, brewing, distillation; Baker's yeast

fodder yeast

blue cheese (injected with spores) Camembert cheese, fermented sausages (salami)

enzymatic preparations

use for the production of butyric acid and solvents (e.g. butanol, acetone, isopropanol) and hydrogen

Candida sp .:

production of enzymes (amylases), antibiotics, insecticides

alcoholic fermentation in winemaking, brewing, distillation; Baker's yeast

fodder yeast

blue cheese (injected with spores) Camembert cheese, fermented sausages (salami)

enzymatic preparations

Penicillium sp .:

production of enzymes (amylases), antibiotics, insecticides

alcoholic fermentation in winemaking, brewing, distillation; Baker's yeast

fodder yeast

blue cheese (injected with spores) Camembert cheese, fermented sausages (salami)

enzymatic preparations

Aspergillus sp .:

production of vitamins, as well as other metabolites (hyaluronic acid, polygalacturonic acid)

alcoholic fermentation in winemaking, brewing, distillation; Baker's yeast

fodder yeast

blue cheese (injected with spores) Camembert cheese, fermented sausages (salami)

enzymatic preparations

Fungi may cause defects such as:

change in color, musty taste and smell

off-flavor and offodor due to proteolysis and lipid hydrolysis

deacidification of fermented products

mycotoxins

putrefaction in canned foods: milk, meat, fish together with blown can defect and decarboxylation of amino acids

What does catalase do?

Catalase is a key enzyme that uses hydrogen peroxide, a non-radical ROS, as its substrate. This enzyme is responsible for neutralization through the decomposition of hydrogen peroxide, thereby maintaining an optimum level of the molecule in the cell which is also essential for cellular signaling processes.

What does oxidase do?

Oxidase is an enzyme that catalyzes oxidation-reduction reactions, especially one involving dioxygen (O₂) as the electron acceptor. In reactions involving the donation of a hydrogen atom, oxygen is reduced to water (H₂O) or hydrogen peroxide (H₂O₂).

What is oxidase and catalase?

Most aerobic and facultatively anaerobic bacteria have catalase!

Oxidase + (Ox +) means that the bacterium has cytochrome c oxidase as a terminal enzyme in the respiratory chain. This enzyme catalyzes the conversion of oxygen to water in the presence of cytochrome c and protons.

Catalase + (Cat +) means that the bacterium has catalase, which converts hydrogen peroxide to oxygen and water.

Clostridium 1

obligate anaerobes, catalase (-)

facultative anaerobes, catalase (-)

obligate aerobes, catalase (+)

found in: soil, sewage, sediments, human and animal digestive tracts

found on mucous membranes, digestive system, plan material, milk, meat

Clostridium 2

heat-resistant spores: efficiency of thermal processes

pleomorphism (X, Y, coccoid)

pleomorphism (X, Y, bacilloid)

pathogenic species from the proteolytic group

may cause spoilage defects – color defects in meat e.g. greening

Clostridium 3

use for the production of butyric acid and solvents (e.g. butanol, acetone, isopropanol) and hydrogen

production of bacteriocins

propionic acid fermentation: propionic acid, acetic acid, CO2

antimicrobial activity of following metabolites: lactic acid, acetic acid, H2O2, bacteriocins

production of dextran - produced in the glycocalyx covering the cells (synthetic blood plasma substitute, slime defects in food products)

Clostridium 4

break down of sugars: saccharolytic clostridia

break down of proteins: proteolytic clostridia

production of bacteriocins: C. botulinum, C. perfringens, C. acetobutylicum

production of bacteriocins: C. sporogenes, C. butyricum

production of bacteriocins: C. botulinum, C. tetani

Clostridium 5

Use in medicine: neurotoxins, botulinum-toxin-complex as a therapeutic agent

Use in medicine: metabolites of C. botulinum, C. tetani

Food spoilage: late blowing of cheese & unpleasant, pungent off-flavor of silage

Food spoilage: pungent off-flavor of silage & bulging of tin cans caused by gas

Food spoilage: early blowing of cheese & unpleasant, tangy-flavor of silage

What happens during putrefaction in canned foods caused by Clostridia?

milk, meat, and fish together with blown can lead to defects and decarboxylation of amino acids

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Food And Feed Preservation - Overview

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