meat hygiene labs | Quizlet

characteristics enterobacteria

gram neg

rods

faculatitive anaerobic

catalase pos

oxidase neg

grows well at 37 degress, some better at 25-30

some motile

worlwide- soil, water, plants, animals

name the bacteria included in enter-bacteria

E. coli

salmonella

Yesenia

shigella

pneumoniae

what's special about the salmonella bacteria

most are motile except s. typhi

most produce hydrogen sulphide

except s.paratyphi

and s. typo produces less than normal

what special about E. coli

capsulated with a k ag

many produce enterotoxin or have other virulence t

factor that increase their invasiveness

what's special about klebsiella

grow on ordinary agar

non-motile

capsulated

what special about shigella

non motile

highly infected

species of shigella

s. dystenteria

s. flexneri

s. boydii

s. sonnei

steps of testing for salmonella

inoculate on mediums XLD and BGA

XLD

• can ferment xylose = decre pH => yellow

• metabolise thiosulfate to H2S => black colonies

BGA

• white —>red

• opaque colonies surrounded by red

• selective for salmonella except typhi

test serology

what does XLD mean

xylose lysine deoxycholate agar

what is XLD used for

selective media for salmonella and shigella

has pH 7.4

contains phenol red so agar is red

how to read results of XLD

if there is sugar fermentation the pH drops

turns agar red to yellow

uses xylose which shigella can't use

yellow= salmonella

what does the salmonella colonies on the XLD agar look like

there are round black colonies because salmonella turns thiosulfate to hydrogen sulphide

what grows on BGA and what inhibited

gram positive INHIBITED

most gram negative bacilli INHIBITED

gram negative rods GROW

what does BGA tell about the colonies that grow

contains phenol red

turns yellow from red when sugar is fermented

lactose non-fermenting is are pink

what does salmonella look like on BGA

white/red colonies w red zone around

what does E. coli and klebsilla look like on BGA

yellow and green w green zone around

what does pseudomonas look like on BGA

red and pink

how to do serology confirmation on salmonella

slide w colony of bacteria and appropriate sera and rock

clumping is a pos reaction

what ag does the agglutination test for

o

h

vi

characteristics of pseudomonas of aerginosa

gram negative aerobic rods

most are motile

free living in water and soil

opportunistic pathogens

optiumum 37-42

produce pigments

what are the 2 pigment of pseudomonas aerginosa

pyoverdin: fluorescent

pyocyanin: blue = blue pus

what agars to use for pyorubin and pyocyanin

king A medium

what agar to use for pyoverdin

king B agar

what happens to p. aerginosa on blood agar

turns red to marine blue

small like jasmine poets

zoonotic infection of p. aerginosa

enteric infection

food poisoning

UTI

resp infcetions

dermatitis and soft tissue infection

affects bones and joints

characteristics of burkholderia

gram - rods

aerobic

non motile

characteristics of b. mullei

gram neg aerobic

coccibacillus

grow on macconkey

non motile

characteristics of b. mpseudomallei

infects humans and plants

causes meliodosis

characteristics of bacillaceae

gram positive bacilli

motile/non-motile

aerobic/non-aerobic

produce ENDOSPORES

colonies of b subtilus

rough creamy white elevated and entire edges

what is caused by B. cereus

food Bourne illnesses

zoonotic problems caused by baccilaceae

cause GIT issues

diarrhea or emetic

the bacteria produce toxins which irritate the mucosa

characterise clostridium

gram positive rods

in pairs or chains

pointed, round, square end

often pleomorphic

aerolotolerant or obligate anaerobes

characterise c. perfringens

aerobic

spore forming

5 types a-e

produce lethal toxin

characterise c. botulism

obligate anaerobic

spore forming

produce neurotoxin- a,b,e

subtypes a-g

incubate of c .perfringens

6-24hrs

how does c. perfringens last in cooked food and symptoms and how long do last

spores are heat stable

symptoms: cramps, diarrhea, vomiting and fever

gone in 24hrs

fatal cases on clostridial necrotising enteritis caused by

types c producing beta toxin

c. sporogens cause what

food spoilage through putrefaction

what is botulism

flaccid paralysis of ANS and motor beginning with the cranial nerves which occurs when the neuromuscular transmission is interrupted by a protein botulism neurotoxin

movement pattern of botulism

cranial nerves

resp muscles

lower extremities

symptoms of botulism

nausea, vomiting, cramps and diarrhoea

neurological symptoms

dry mouth and blurred vision

peripheral muscle weakness, dysphagia and dysarthia

how is the beta toxin stable

pH 3.5-6.5

dissociates at alkaline conditions

spores are heat stable

how to kill botulism spores

30mins @80

10mins @ 100

what is the 12-D process

heating botulism spores to 121.1. for 2.8 mins

detection of aerobic spore forming

heat serial dilution at 80 for 10mins

inoculate .5ml on 2 plates

incubate

gram stain

examine

Schaeffer fultor method

examination of spores

fix to the slide

malachite green het 3 times

wash

add safranin for 30 secs

observe

endospores are bright green

detection of botulism toxins

detected on mice and gineua pigs

present give antitoxin

detection of anaerobic spore forming

inoculate 2 Wrzosek broth w 1g meat

heat 80 for 10mins

inoculate both and gram stain

up until now same as aerobic

postive for gram + rods

put 1 drop from 1 broth to WILSON BLAIRE

heat @ 45

mix leave and add water

will be black colonies = + for anaerobic spores

characteristics of staphylococcus

gram + cocci

catalase +

oxidase negative

types of staphylococcus

s. aureus

s. epidermis

s. saprophyticus

characteristics of s. aureus

potential pathogen

produces coagulase

yellow and large colonies

hemolytica

what are the properties of a pathogenic strain of staphylococcus

beta hemolysis

liquefaction of coagulataive serum

increase fibrinolysis

hematoxin

dermatoxin

lathaltoxin

zoonotic of staphylococcus

important cause of food Borne illnesses as it produces enterotoxin

human carrier

food product and animal origin

characteristic of s. epidermidis

can't produce coagulase

white small colonies

non-hemolyitca

charcterise streptococcus

gram + in chains and pairs

types of hemolysis

types of hemolysis of streptococcus

alpha hemolysis: oxidation of iron in the haemoglobin green

bete hemolysis: complete rupture of RBCs clear

gamma hemolysis: no hemolysis

characterise s. pyrogens

gram +

non motile

non spore forming

catalase +

facultative anaerobes

how to identify staphylococcus

liquid medium: Giolitti- cantoni used to enrich stay aureus

causes blackening of the medium is +

then subculture to Baird Parker

characteristics of enterococcus

facultative anaerobes

tolerant to extreme temp, pH and chloride conc.

characterise nocardia

gram + rods

smooth moist colonies that have a powdery appearance and have a mildew odour

causes progressive pneumonia

what are under the fungi bracket

moulds

yeast

higher fungi- saprophytes

characterise fungi

chemoterotrophs

aerobic

contain chitin in the wall

produce mycotoxins

most important mycotoxins

aflatoxin

ochratoxins A

fumonisms

trichthecenes

zearalenones

types of diseases caused by fungi

superficial

subcutaneous

systemic

oppourtunistics

agars to detect fungi

sabouruda

synthetic

czapeks medium

2 forms of catalase

enzyme bound: clumping factor

free enzyme: converts prothrombin causing fibrinogen to fibrin-clot

where will bacteria be present and least likely

organs w no contact to the exterior may be regarded as sterile

a slaughter if bacteria/septicemia present bacteria are likely to be found in the spleen, lymph node and muscular tissue

intestinal bacteria could migrate to systemic migration when the barrier is down

examination of animals and meat for slaughter and food

ante-mortem

gross post-mortem

lab tests

when will bacteriology lab not be required

when they exhibit marked pathological changes but not required when they show pathological changes of non-infectious nature= condemned without bacteriology

when will bacteriology be necessary

slaughtered in emergency

excreting food poisoning organisms

slaughtered without antemortem

haven't been eviserated within 1hr of slaughter

slaughtered due to systemic disturbances

pathological changes in the the post mortem

list of material submitted for examination

2 complete muscles w faces

(1 from hinquarter/ 1 from forequarter and then cubes 8cm from opposite each side)

prescapilular/auxiallry lymph nodes or iliac node

spleen if ENLARGED

kidney

SM:whole liver and gallbladder

LM:2 fists of liver, portal veins, gallbladder and lymph nodes

parts of pathological changes and LN

portion of small intestine w mesenteric lymph nodes

what happens with received samples in the lab

examined immediately

put on sterile plate

visible changes noted

burn surface

cut with sterile knife and inoculate

solid mediums used for bacteriology

nutritive agar

baird parker agar

brilliant green agar

blood Agar

liquid mediums used for bacteriology

MRSV

wrzoseks broth