Microbiological Criteria Flashcards
(34 cards)
What is a microbiological criterion?
A criterion defining the acceptability of a product, a batch of foodstuffs or a process, based on the absence, presence or number of microorganiisms and/or on the quantity of their toxins/metabolites, per units of mass, volume, area or batch
What is the difference between microbiological criterion and food safety objective/performance objectives?
FSOs and POs which only represent limits and MC consists of several aspects:
* microoragnisms of concern have to be stated
* A qualititive or quantitative analytical method validated and chosd to give a sufficienctly reliable estimate
* critical limits based on data appropriate to the food
* Sampling plan inclusing the sampling and decision criteria for a lot
What are the two different types of microbiological criteria in the EU?
Food safety criteria
Process hygiene criteria
What is food safety criteria?
Criterion defining the acceptability of a product or a batch of foodstuff applicable to the products places on the market
Defined only for the pathogens/foodstuffs with efficienct contribution to public health
What is process hygiene criteria?
Criterion indicating the acceptable functioning of the production process
Sets an indicative contamination value which corrective actions are required
Why do we need microbiological criteria?
- Useful for validation and verification of HACCP based on process and procedurees, and other hygiene control measures
- Assess the acceptability of a batch of food
- Communicate the level of hazard control
- Offers some assurance
What is wrong with non-destructive methods of sampling?
recovery rate of bacteria is not 100%
Microbiological criteria cannot be applied without microbiological testing
What can testing be used for?
- Acceptance of a lot of raw materials, food ingridients or end products
- Shelf life of foods
- Monitoring production lines
- Monitoring hygienic status of the processing environment
- verification of GHP and HACCP
- Baseline studies for the occurence of specific microbes at stages
- Surveillance at certain stages of production
- Outbreak investigations
What are the microbiological standards (mandatory)
- Used to determine the acceptability of a food with regard to a regulation or policy
- Established by regulatory authorities
- Foods not meeting the standard are subject to removal from the market
What are the microbiological specifications?
- Used by buyers of a food purchasing a product that may be unacceptable safety and quality
- Buyers throughout the food systems establish microbiological specifications for materials they produce
- Specifications are advisory and the materials are sampled periodically
What are the microbiological guidelines?
- Established by regulatory authorities, industrial trade associations or companies
- Indicate the expected microbial content of food with practices
- Food companies use guidlines as a bases to design and assess
- Advisory in nature
Why is a representitive sample taken?
Sampling a food lot would destroy it therefore a representitive sample is a compromise
What is defined as a criterion?
- What type of hazard (pathogen, genetic sequence), qualitative or quantitative
- Food Category
- Production or processing steps involved
- Sampling plans
- Interpretation
What are indicator organisms and pathogens?
Indicator organisms:
* General microbiota- synonyms: total aeorobic count, aerobic count- hygiene status of process
* Faecal coliforms (E.coli)- indication of faecal contamination
Pathogens- Salmonella, listeria monocytogenes, staphylococcus aureus
What should the sample plan define?
What are the different types?
‘The probability of detecting microorganisms in a lot’
Two class or three class sampling plan
- When are two class sampling plans used?
- What are its specficiations
- Used almost exclusively for pathogens, based on presence/absence
- Specifications:
N= number of sample units from a lot to be examined
M= maximum acceptable number of relevant bacteria
C= maximum acceptable number of sample units that may exceed the value of M
Either satisfactory- counts below M or unsatisfactory
- When is a three class sampling plan used?
- What are the specifications?
- How is it interperated?
- Often applied for indicator organisms
- Consist of the specifications- n, c, m and M
c = number of sample units giving values between m and M
M is used to seperate the acceptable from the unsatisfactory
Interpretation
Satisfactory if below m
Acceptable if a maximum of c/n values are between m and M and the rest of the values are < m
Unsatisfactory if one or more of the values observes are >M or more than c/n values between m and M
What factors affect the development of microbiological criteria?
- The availability of a risk assessment
- Dose-response data
- Consumer exposure data
- Defined ALOP or FSO/PO
- Data on microbial levels typically encountered in a food
What decides what type of sample is taken?
May be dictated by regulations
Depends on material to be tested:
* Excision (carcass)
* Wet/dry swabbing (carcasses and surface equipment
* Whole carcass rinse (poultry)
* Meat sample (retail)
* Batch sample (food products, raw ingridients)
Where are samples analysed?
In-house- poultry widely, must be accredited or supervised by accredited
Commercial- must be accredited and used recognised methods (ISO)
What are the stages in sample processing?
Sampling
Transport
Removal of bacteria from sample
Examine for target organism
Confirm suspect colonies
Calculate and report results
What are the two categories for sampling methods?
Destructive- excision with scalpel or borer
Non-destructive- wet/dry swabs
What are the sample sites for TAC and enterobacteriaeae on cattle sheep and pigs?
Cattle- rump, flank, brisket and neck
Sheep- flank, brisket, thorax lateral, breast
Pig- ham, belly, back, Jowl
What is the sampling area for salmonella?
