Microbiology and HACCP For Surimi Seafood

Surimi Seafood Microbiology

• Production and storage• Microbial quality• Microbial safety • Pasteurization studies• Non-thermal processing

• HACCP• Microbial standards• Packaging• Fermented products• Rapid test kits

Microbiology of Surimi During Production and Storage

Microbial Quality and Safety of Surimi Seafood Depends On:

• Microbial load in the raw surimi• Microbial load in ingredients• Processing time/temperature abuse• Equipment sanitation• Employee hygiene

Figure 1. Aerobic Plate Count

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a b c d e f g h

Processing step

Log

CF

U/g

Surimi Crab Leg

Flaked SurimiCrab MeatSurimi Scallops

a = surimib = surimi plus ingredientsc = first cook/rope formationd = color addition

e = second cookf = flaking or choppingg = packagingh = “pasteurization”

Figure 2. Coliform Counts

00,5

11,5

22,5

33,5

4

a b c d e f g h

Processing step

Log

Tot

al C

olif

orm

/g

Surimi Crab Leg

Flaked SurimiCrab MeatSurimi Scallops

a = surimib = surimi plus ingredientsc = first cook/rope formationd = color addition

e = second cookf = flaking or choppingg = packagingh = pasteurization

Figure 3. Fecal Coliform Counts

0

0,5

1

1,5

2

2,5

3

a b c d e f g h

Processing step

Log

Fec

al C

olif

orm

/g

Surimi Crab Leg

Flaked SurimiCrab MeatSurimi Scallops

a = surimib = surimi plus ingredientsc = first cook/rope formationd = color addition

e = second cookf = flaking or choppingg = packagingh = pasteurization

Equipment Sanitation

• Belt conveyor 1,800,000/cm2

• Container of mixed paste 25,000/cm2

• Inner wall of mixer 540/cm2

Surimi Seafood Shelf Life

Days at: 15oC 10oC 5oC 0oC59oF 50oF 41oF 32oF

Surimi crab legs 4 14 >28 >28Flaked surimi

crab meat <3 <4 <7 14

Figure 4. APC: Surimi Crab Legs

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0 10 20 30

Days of Storage

Log

CF

U/g 15C

10C5C0C

Figure 5. APC: Flaked Surimi Crab Meat

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10

0 10 20 30

Days of Storage

Log

CF

U/g 15C

10C5C0C

Microbial Quality of Surimi Seafood: Bacillus Species and Other Gram-positive Bacteria

Pasteurization

• Has no effect on bacterial spores, i.e., Clostridium and Bacillus species

• Bacillus species are prime spoilers in air-packaged surimi seafood

Figure 6. Microbial Flora of Vacuum-Packed Flaked Surimi Crab Meat

0%

20%

40%

60%

80%

100%

0 4 8 13 19

Days at 22oC (71.6o F)

% C

omp

osit

ion

UnknownGram-NegativeGram-Positive

0%

20%

40%

60%

80%

100%

% C

ompo

siti

on

0 1 2 3 4 5 6

Days of Storage

Figure 7a. Microbial Isolates From

Surimi Crab Legs Stored at 15oC (59oF)

OtherPseudomonasBacillus

0%

20%

40%

60%

80%

100%

% C

ompo

siti

on

0 3 6 9 12 15 18

Days of Storage

Figure 7b. Microbial Isolates From

Surimi Crab Legs Stored at 5oC (41oF)

OtherPseudomonasBacillus

0%20%40%60%80%

100%

%

Com

posi

tion

0 7 14 21 28 35 42

Days of Storage

Figure 7c. Composition of Microbial Isolates From Surimi Crab Legs Stored

at 0oC

OtherPseudomonasBacillus

Microbial Safety of Surimi Seafood: Listeria

monocytogenes, Clostridium botulinum and Other Bacteria

L. monocytogenes

• 1988 surimi survey found 29% of samples positive

• 1988 U.S. Class I recall of imitation crab meat produced in Japan and distributed in three states

Table 1. Surimi Seafood Recalls Due to L. monocytogenes

• Imitation crab meat products 7/28/99 • Imitation crab spread 9/17/97• Imitation king crab legs 8/6/97• Imitation crab meat chunks 6/12/96• Imitation crab meat salad 9/30/92• Seafood salad 7/2/92

Clostridium botulinum

• Strict anaerobe• Grows above 38°F• No instances reported from surimi seafood• C. botulinum type E and nonproteolytic types

B and F are the target bacteria for FDA’s pasteurization processes– 6-D process = 90°C (194°F) for 10 minutes

Generation Times (Hours) for Pathogens in Surimi Seafood

15oC 10oC 5oC 0oC59oF 50oF 41oF 32oF

Aeromonas hydrophila 18 48 194 -Salmonella species 11 34 - -Staphylococcus aureus 29 46 - -Yersinia enterocolitica 11 26 77 166

Pasteurization Studies for Surimi Seafood

• Inoculated pack studies with Enterococcus faecium– 93°C (199.4°F) 5 minutes– 85°C (185°F) for 15 minutes– 75°C (167°F) for 15 minutes

• Yielded 6 log reduction of E. faecium– Process also effective against C. botulinum Type E (85 and

93°C), L. monocytogenes, enteropathogenic E. coli, Salmonella, Yersinia entercolitica, and Vibrio

• Ineffective against C. botulinum Type B

Pasteurization Studies for Surimi Seafood

Temperature Time D-Values(min.) L.m. C.b.(E) C.b.(B)

93°C (199.4°F) 5 16,200 52 0.785°C (185°F) 15 5,400 24 0.675°C (167°F) 15 350 2.2 0.1

Microbiological Implications of Novel Surimi Processing

Technologies• High pressure– 200-400 MPa– Effective against Vibrio, Listeria, Salmonella– Ineffective against pressure resistant species and spore

forming Bacillus and Clostridium species

• Electron beam– Untested

HACCP and Surimi Seafood

• Preventive system of food safety control• Based on – Identified hazards– Critical control points– Monitoring records

Metal Fragments

• Hard or sharp objects >7 mm in size are a potential hazard from laceration, perforation wound, and secondary infections

• Hard or sharp objects <7 mm in size are a possible hazard for high risk (e.g., infants, elderly) individuals

• Controls can include frequent inspections of cutting, portioning, blending, or other mechanical equipment for damage, or use of a metal detector

Pasteurization

• Eliminates targeted pathogenic bacteria and also extends product shelf life

• Pathogens in packaged products indicates inadequate pasteurization, or post pasteurization contamination, and time/temperature abuse

• Critical aspects: temperature of heating medium, length of pasteurization cycle, package thickness, package integrity, product formulation, and microbial quality of the cooling medium

Cooling

• Rapid cooling prevents growth from Bacillus and Clostridium

• 60°C (140°F) to 21.1°C (70°F) in 2 hours• To 4.4°C (40°F) within another 4 hours

Refrigerated Storage

• Refrigerated storage below 4.4°C (40°F) prevents growth of pathogens

Microbial Recommendations for Ready-to-eat Seafood

n c m MAerobic plate count 5 2 105 106

E. coli 5 1 11 500S. aureus 5 0 103 -V. parahaemolyticus 10 1 102 103

FDA Tolerance Levels: Vacuum Packaged Ready-to-eat Seafood

C. botulinum Presence of cells, Enteropathogenic E. coli 103/gL. monocytogenes PresenceSalmonella PresenceS. aureus 104/g or toxin positive V. cholerae PresenceV. parahaemolyticus 104/gV. vulnificus Presence

Microbiological Considerations in Packaging of Surimi Seafood

• Nitrogen and carbon dioxide packaging reduce fat and pigment oxidation and reduce spoilage bacterial growth

• Aseptic packaging requires a sterile product and may not be feasible

New Surimi Seafood Products Utilizing Fermentative Bacteria

• Fermented pollock kamaboko– pH 4.5– Sour tasting

• Fermented chum salmon surimi• Sensory studies have not been conducted

Reliability and Efficacy of Rapid Microbiological Procedures

• Traditional methods– APC with petri dishes or PetriFilm

• Rapid test kits for L. monocytogenes– 1-2 days instead of 5-7 days

Conclusion

• Surimi seafood Products are ready-to-eat– Safety and quality concerns remain– HACCP can help ensure a safe product

• The use of the term “pasteurization” should be discouraged or the process needs to be further studied