Intervention/decontamination strategies for control of foodborne pathogens at slaughter Flashcards
What are the 3 methods of stunning?
- Bolt stun guns
- Modified atmosphere
- Electrical current
Describe sticking and bleeding and its considerations
- Shortest possible duration between stunning and bleeding
- Bleeding time: between a minimum of 4 to 6 minutes
- Two types of bleeding: Jugular and pre thoracic
Where on the carcass must be tied?
The oesophagus and rectum
Describe skinning (dehiding) and its technique
- General hygiene
- Knife technique
- Udder removal
- Mechanical pulling of the hide: downwards is most hygienic
The evisceration platform must be designed to:
- Offer ergonomic working conditions for the operator
- Minimise contamination of the carcasses during the work
Running water must be at what temp to clean knifes, tools and other equipment?
82 degrees
What are the main sources/routes of microbial contamination of carcasses during dressing?
- Microorganisms from hide
- Microorganisms from guts
- Airborne microorganisms
- Microorganisms from equipment
- Microorganisms from people
What are the 3 main foodborne pathogens at the abattoir?
- E.coli
- Salmonella
- Listeria monocytogenes
What are the main routes of carcass microbial contamination from hide?
- Hide microbiota is regularly transferred from the hide onto carcass meat during dehiding
Direct transfer: Via accidental in-rolling of hide
Indirect routes: - Via workers’ hands
- Via contaminated knives, equipment, aprons, etc
- Via aerosols generated during manipulation with hides (especially after mechanical pulling)
What are interventions in abattoirs?
Actions taken during slaughter and processing to reduce microbial contamination of carcasses
What are some cattle hide interventions?
Chemical washes with vacuuming and immobilisation treatments
Which hide treatments can be used pre-evisceration?
- Animal washing
- Shearing or clipping the hide
- Washing hides with chemicals
- Chemical dehairing
- Knife trimming
- Stream vacuuming
Which hide treatments can be used post-evisceration?
- Knife trimming
- Stream vacuuming
- Steam pasteurisation
- Chilling and simultaneously spraying with chemicals
- Washing with chemicals
Describe the practicalities of pre-slaughter washing of animals
- Technically difficult and hazardous for workers
- Animal welfare and meat quality concerns – impossible to apply harsher cleaning or decontaminating agents
- Hide of washed animals eventually becomes again re-contaminated until skinning point
Describe post-slaughter pre-skinning treatment of hides
- Proactive, deals with “causes”
- No animal welfare concerns - much harsher treatments possible
- Since the hide is inedible, much aggressive and harsher treatments possible
What are some possible approaches to hide treatments
- Removal of bacteria from the hide: Water-washing is ineffective microbiologically
- Decontamination: to eliminate/kill bacteria on the hair: it is not possible to completely eliminate/kill all bacteria on hides
- Immobilization: to “stick” bacteria to the hair: no need to kill the bacteria, only to prevent their transfer onto carcass meat
What are the limitations of hide decontamination techniques?
- Effectiveness: reported microbial reductions achievable were relatively limited
- Cost and space restrictions: Decontamination equipment is usually expensive and require large space for installation
- Environmental pollution with chemical waste
- Impact on hides value
What is an alternative to the pre slaughter clipping of cattle on farm and in lairages?
The VacClip® system to remove hide contamination on line
How does the VacClip® system prevent airborne contamination?
Removes dirt within flexible hosing to an enclosed container located away from the kill line
Describe the principles of the immobilization treatment
- “Gluing” of bacteria to the hide: various compounds possible, so far the most promising is 23% solution of food-grade insect-produced resin Shellac in ethanol
- Spraying application preferred
- Post-slaughter but pre-skinning application
- The cleaner/dryer the hides, the better “gluing” of bacteria
Which of the hide treatments has the highest efficacy in reducing carcass contamination?
Chemical dehairing
What are some carcass meat decontamination treatments?
- Carcass wash: Hot water (>74oC)
- Carcass decontamination: Steam Pasteurization SystemTM (105oC)
- Steam vacuuming (spot treatment)
- Carcass decontamination - organic acids: lactic, acetic, citric, fumaric
- Irradiation
Describe steam vacuuming
- physical removal of visible faecal contamination and bacteria
- used on locations prone to contamination
- used directly if visible faecal spots <1”
- knife trimming first if >1”, then steam
- reductions up to 2 log cycles
Describe ‘multiple hurdle technology’
Combination of 2 to 5 interventions:
- Hide on carcass wash
- Pre-evisceration rinse/spray (hot water/lactic acid)
- Steam vacuum (spot treatment)
- Post evisceration carcass wash (hot water/organic acids)
- Steam or hot water pasteurization
- Final acid rinse/spray
- Spray chill
- Post chill wash
