Aquatic VPH: Food Borne Parasites

What are 4 different causes of fish spoilage?

1) Autolysis

• Enzymes in fish tissue break down muscle after death, leading to softening and off-ish flavors

2) Bacterial Growth

• Environmental flora (Pseudomonas, Aeromonas, Vibrio) multiply quickly

• Produce slime, odors, and discoloration

3) Storage Conditions

• Warm temps accelerate autolysis and bacterial growth

• Poor handling (delayed chilling, dirty water) worsens spoilage

4) High water content of fish flesh

• Creates ideal conditions for bacterial activity

** Rapid chilling is ESSENTIAL to reduce spoilage

What are the common genera of environmental bacterial flora of fish?

• Aeromonas

• Flavobacterium

• Pseudomonas

• Vibrio

  • Particularly an issue in shellfish; concentrate this bacteria within their tissues

• Serratia

• Photobacterium

• Clostridium

• Bacillus

• LISTERIA

  • Can be found naturally in aquatic environments

Some act as spoilage organisms, others can be opportunistic human pathogens

• These would be termed “natural” contaminants… cause the fish meat to spoil and have a rotten taste

Any other contamination with different types of bacteria (ex: staphylococcus aureus, e. coli, salmonella) would be an UNNATURAL contaminant

• AKA a hygiene failure

• Salmonella → cross contamination w/

What are 6 different controls against bacterial hazards you could do to mitigate the risk of contamination of fish meat?

• Pre-harvest fasting to reduce gut content

  • Different for different types of fish

    • Warm water fish have faster metabolisms; will be quicker to fast

    • Cold water fish have slower metabolisms; will take longer to fast (sometimes days)

• Hygienic slaughter & handling

• Rapid chilling using potable, chlorinated water

• HACCP: high-risk vs low-risk separation

• Removal of biofilms by effective disinfection

• Environmental & product microbiological monitoring

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