Module 12 wk2 Flashcards
( food microbiology)
T/F the more bacteria the longer the shelf life?
False - the more bacteria the shorter the shelf life
Why is food sampled?
- checks on hygienic production and handling techniques
- quality control and shelf life performance
- suspencion of being the cause of food poisoning
or as a result of consumer complaint - verification of quality of imported food
Give a list of microbiological tests to monitor food?
Total viable counts
Counts of coliforms
Counts of psychotrophs
Presence of pathogens – once make you ill
Presence of bacterial toxins – that they produce
Presence of fungi
Presence of mycotoxins – some are carsogenic so important
Indicator organisms – E. coli, enterococci
Describe the procedure of examining samples of food
- Refrigerate at 4°C until examination within 24 hours
- Homogenise (broken up to evely distribute) for 2 minutes in 100ml 0.1% buffered peptone water/0.9% saline 250 cycles stomacher or homogenised
- 10 fold dilutions in 0.1% peptone in 0.85% saline then plate
- TVC and Enterobacteriaceae
when interpreting results what does the presence of fecal organisms indicate?
Need for further investigation
What does the absence of target pathogens mean?
Means that the test only provides a degree of probability that they are not present in the food
Describe quantitive sampling
- The sample size is known
- There is no loss in storage
- Particles
- Viable counts
What do you do with templates when testing?
PLaces it over carcass and rub swap all over space, culture or put in enrichment media
What is total viable counts?
- It is the basis of international agreements and standards - for carcase meat and minced meat
Out of viruses, bacteria, parasites, and fungi which can multiply in food?
bacteria and fungi
5 types of bacterial pathogens in food?
- salmonella
- campylobacter
- E.coli
- clostridium - p and b
- Staphylococci
once you have quantitative culture what do you do next?
- pre-enrichment in peptone water and then enrichment in selective broth
- plate culture from enrichment broth on selective medium
How is Samonella confirmed in lab?
Biochemically
how is campylobactor confirmed in lab?
By API strip
Describe how campylobactor samples are retrieved from chickens?
Birds are hung unside down so feacal matter goes down to head and neck contaminating it so that is where they take sample from
T/F some people carry Staph. aureus all the time, some intermittently and some none.
Trueeeee ew
(girlie pop you carry it so idk why your saying ew)
How do you confirm Listeria?
By PCR to check for the listeriolyosin gene
T/F clostridium botulinum still today is fatal if ingested?
False - used to be fatal and paralyse but now we are able to neutalize toxin and have ICU
(Food standards + Food spoilage)
Whats does microbiology criteria provide?
- Provides guidance on acceptability of food and the manufacturing process
Provides objective and reference points to assist Food Business Operatives (FBO’s) to manage and monitor the safety of food - Can be used to validate and verify HACCP procedures and hygiene measures
How often should sampling take place on a meat plant?
Regular sampling should be taking place in the meat plant at least weekly
How many carcases are used per week to sample?
5
Using the destructive method what samples are taken?
4 tissue samples of 20cm^2
Using the non-destructive method what samples are taken?
100cm^2 sample
what organism is found in read-to-eat foods?
Listeria monocytogenes
what are actions if the criteria are not met for individual batches that the FBO must do
The FBO must ensure that individual batches that do not meet the criteria are disposed of safely or are reprocessed in an approved fashion
where do the microorgaminsm in food derved from?
raw materials, contamination during their production, in storage and by the purchaser
what are the different mechanisms of spoilage?
- Sugar fermentation with acid and gas production
- Protein hydrolysis – bacterial enzymes – proteases
- Digestion of complex carbohydrates – fungi – pectinases
- Lipolysis – lipolytic enzymes
- Oxidation of organic acids and alcohols
- Surface growth
T/F Staphylococci is a gram-positive spoilage organism?
True
T/F E.coli is a gram negative spoilage organism?
True
what are moulds sourced from ?
air, dust and condensation
If you see mould in black spots what is it?
cladosporium
If you see mould in white spots what is it?
sporotrichum
If you see mould in whiskers what is it?
Mucor
Bluish green moulds are?
Aspergillus, penicillium
(Endocrine Pathology - Intro)
What are the three types of intracellular signaling?
- autocrine
- paracrine
- endocrine
what is autocrine signalling?
cells respond to signals that they create themselveswh
what is paracrine signalling?
molecules produced by one cell act on neighboring cell
What is endocrine signalling?
Hormones produced by endocrine organs get into circulation and act on distant target cells
What is the definition of an endocrine gland?
Group of specialised epithelial cells that synthesis, store and directly release hormones into blood
What kind of hormones do endocrine gland release?
polypeptides, steroids, AA derivatives
what is an endocrine gland made up of?
An endocrine gland is made of cords and packets of specialized epithelial cells in a scanty fibrous stroma, that in turn is well vascularised by sinusoids/capillaries.
Describe primary endocrine hypofunction
- Failure of glandular development
- destruction of secretory cells
- biochemical defect in the synthetic pathway (looks normal, function not)
Describe the secondary mechinism of endocrine hypofunction
Destructive lesion decreases trophic hormones so reduced activity in second organ so signalling organ has problem meaning other does too
Describe the primary mechanism of endocrine hyperfunction
Abnormal cells secrete hormone in excess of bodily requirement s
Describe the secondary mechanism of endocrine hyperfunction
Abnormal cells in one organ produce too much trophic hormone which increases activity in the target organ
when there primary hyperfunction what hormone causes Acidophil adenoma (pituitary gland)? and what sign/lesion do we see?
Growth hormone and acromegaly
when there is primary hyperfunction what hormone causes Phaeochromocytoma? and what sign/lesion do we see?
noradrenaline and hypertension
when there is primary hyperfunction what hormone causes Parathyroid gland chief cell adenoma? and what sign/lesion do we see?
paratyroid hormone and fibrous osteodystrophy
when there is primary hyperfunction what hormone causes Pancreatic β-cell adenoma / carcinoma? and what sign/lesion do we see?
insulin and hypoglyceamia
when there is primary hyperfunction what hormone causes Thyroid follicular cell adenoma? and what sign/lesion do we see?
T3,T4 and increase in basal metabolic rate
What are the clinical results of endocrine disease?
Functional and clinical pathology abnormalities affecting one or more body system can be seen
What does primary anterior pituitary hypofunction cause?
- Aplasia
- congenital, toxic and viral
- destruction of the space-occupying lesion
- cystic Rathkes pouch
- abscess, granuloma
- neoplasm
what does secondary pituitary hypofunction cause?
Hypothalamic malfunction
What is the posterior pituitary hypofunction clinical syndrome?
Diabetes insipidus
What is the type of diabetes insipidus and what is it caused by when there is primary posterior pituitary hypofunction?
central DI
It is caused by the destruction of the pars nervosa meaning no ADH is produced
What is the type of diabetes insipidus and what is it caused by when there is secondary posterior pituitary hypofunction?
Nephrogenic diabetes insipidus which restricts renal tubules can’t respond to the ADH
Clinically what can be seen with central diabetes insipidus?
- ADH deficiency
- Lack of H2O reabsor[tion in tubules
- This leads to dilute urine, hypernatremia and dehydration
- PU/PD and low USG
What is the most common cause of pituitary hyperfunction?
Functional neoplasms within pituitary
In dogs where is it most common to see adenoma in the pituitary?
Pars Distalis
In horses where is it most common to see adenoma in the pituitary?
Pars Intermedia
In PPID pars intermedia dopamine is decreased all year round, if there is no inhibition of this what is caused?
Melanotrophs of pars intermedia synthesize excessive hormones, hyperplasia, micro and macroadenomas develop
An enlarged pituitary compresses the hypothalamus and causes clinical signs, what are these?
There is abnormal regulation of appetite, temp, seasonal sleep rhythms and hair growth
What are the clinical signs of PPID?
- Polyphagia, polyuria, polydipsia
- Hyperglycaemia
- Laminitis
- Generalised hyperhidrosis (sweating)
- Somnolence
- Striking hypertrichosis - hirsutism
What kind of disorder is Equine metabolic syndrome?
complex
What does Equine metabolic syndrome cause?
- Increased regional adiposity
- Insulin resistance - can lead to laminitis
- Altered metabolism due to adipocyte dysfunction leading to increased thrombosis, inflam and oxidant stress, altered vascular endothelial cell function
How would you differ between PPID and EMS?
- age of onset - EMS gen younger
- Additional clinical signs suggest PPID such as failed coat shed, excess sweating and skeletal muscle atrophy
- positive diagnostic test for PPID - increased plasma ACTH without pain
T/F Both PPID and EMS can coexist in one individual?
Trueeeeeeeeeeee SLAY
(Endocrine Pathology - Examples)
What is the term for adrenal cortical hypofunction?
Hypoadrenocorticism - addisons disease
What is hypoadrenocorticism caused by?
Adrenal cortical atrophy
What age and sex of dogs does hypoadrenocorticism affect? and what is the exception to this?
Typically young to middle-aged dogs, slightly more common in females, apart from breeds with a genetic predisposition
(eg Portuguese water dogs, bearded collies and standard poodles)