Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products

Miia Lindström (Corresponding Author), Mari Nevas, Sebastian Hielm, Liisa Lähteenmäki, Michael W. Peck, Hannu Korkeala

Research output: Contribution to journalArticleScientificpeer-review

33 Citations (Scopus)

Abstract

Thermal inactivation of nonproteolytic Clostridium botulinum type E spores was investigated in rainbow trout and whitefish media at 75 to 93°C. Lysozyme was applied in the recovery of spores, yielding biphasic thermal destruction curves. Approximately 0.1% of the spores were permeable to lysozyme, showing an increased measured heat resistance. Decimal reduction times for the heat-resistant spore fraction in rainbow trout medium were 255, 98, and 4.2 min at 75, 85, and 93°C, respectively, and those in whitefish medium were 55 and 7.1 min at 81 and 90°C, respectively. The z values were 10.4°C in trout medium and 10.1°C in whitefish medium. Commercial hot-smoking processes employed in five Finnish fish-smoking companies provided reduction in the numbers of spores of nonproteolytic C. botulinum of less than 103. An inoculated-pack study revealed that a time-temperature combination of 42 min at 85°C (fish surface temperature) with >70% relative humidity (RH) prevented growth from 106 spores in vacuum-packaged hot-smoked rainbow trout fillets and whole whitefish stored for 5 weeks at 8°C. In Finland it is recommended that hot-smoked fish be stored at or below 3°C, further extending product safety. However, heating whitefish for 44 min at 85°C with 10% RH resulted in growth and toxicity in 5 weeks at 8°C. Moist heat thus enhanced spore thermal inactivation and is essential to an effective process. The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processes rainbow trout were observed.
Original languageEnglish
Pages (from-to)4029-4036
JournalApplied and Environmental Microbiology
Volume69
Issue number7
DOIs
Publication statusPublished - 2003
MoE publication typeA1 Journal article-refereed

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Clostridium botulinum type E
Clostridium botulinum E
Fish Products
smoked fish
fish products
Salmonidae
heat inactivation
Vacuum
Spores
spore
Fishes
spores
Hot Temperature
Oncorhynchus mykiss
fish
rainbow
heat
smoking (food products)
Muramidase
Humidity

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Lindström, Miia ; Nevas, Mari ; Hielm, Sebastian ; Lähteenmäki, Liisa ; Peck, Michael W. ; Korkeala, Hannu. / Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products. In: Applied and Environmental Microbiology. 2003 ; Vol. 69, No. 7. pp. 4029-4036.
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title = "Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products",
abstract = "Thermal inactivation of nonproteolytic Clostridium botulinum type E spores was investigated in rainbow trout and whitefish media at 75 to 93°C. Lysozyme was applied in the recovery of spores, yielding biphasic thermal destruction curves. Approximately 0.1{\%} of the spores were permeable to lysozyme, showing an increased measured heat resistance. Decimal reduction times for the heat-resistant spore fraction in rainbow trout medium were 255, 98, and 4.2 min at 75, 85, and 93°C, respectively, and those in whitefish medium were 55 and 7.1 min at 81 and 90°C, respectively. The z values were 10.4°C in trout medium and 10.1°C in whitefish medium. Commercial hot-smoking processes employed in five Finnish fish-smoking companies provided reduction in the numbers of spores of nonproteolytic C. botulinum of less than 103. An inoculated-pack study revealed that a time-temperature combination of 42 min at 85°C (fish surface temperature) with >70{\%} relative humidity (RH) prevented growth from 106 spores in vacuum-packaged hot-smoked rainbow trout fillets and whole whitefish stored for 5 weeks at 8°C. In Finland it is recommended that hot-smoked fish be stored at or below 3°C, further extending product safety. However, heating whitefish for 44 min at 85°C with 10{\%} RH resulted in growth and toxicity in 5 weeks at 8°C. Moist heat thus enhanced spore thermal inactivation and is essential to an effective process. The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processes rainbow trout were observed.",
author = "Miia Lindstr{\"o}m and Mari Nevas and Sebastian Hielm and Liisa L{\"a}hteenm{\"a}ki and Peck, {Michael W.} and Hannu Korkeala",
year = "2003",
doi = "10.1128/AEM.69.7.4029-4036.2003",
language = "English",
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Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products. / Lindström, Miia (Corresponding Author); Nevas, Mari; Hielm, Sebastian; Lähteenmäki, Liisa; Peck, Michael W.; Korkeala, Hannu.

In: Applied and Environmental Microbiology, Vol. 69, No. 7, 2003, p. 4029-4036.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Thermal inactivation of nonproteolytic Clostridium botulinum type E spores in model fish media and in vacuum-packaged hot-smoked fish products

AU - Lindström, Miia

AU - Nevas, Mari

AU - Hielm, Sebastian

AU - Lähteenmäki, Liisa

AU - Peck, Michael W.

AU - Korkeala, Hannu

PY - 2003

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N2 - Thermal inactivation of nonproteolytic Clostridium botulinum type E spores was investigated in rainbow trout and whitefish media at 75 to 93°C. Lysozyme was applied in the recovery of spores, yielding biphasic thermal destruction curves. Approximately 0.1% of the spores were permeable to lysozyme, showing an increased measured heat resistance. Decimal reduction times for the heat-resistant spore fraction in rainbow trout medium were 255, 98, and 4.2 min at 75, 85, and 93°C, respectively, and those in whitefish medium were 55 and 7.1 min at 81 and 90°C, respectively. The z values were 10.4°C in trout medium and 10.1°C in whitefish medium. Commercial hot-smoking processes employed in five Finnish fish-smoking companies provided reduction in the numbers of spores of nonproteolytic C. botulinum of less than 103. An inoculated-pack study revealed that a time-temperature combination of 42 min at 85°C (fish surface temperature) with >70% relative humidity (RH) prevented growth from 106 spores in vacuum-packaged hot-smoked rainbow trout fillets and whole whitefish stored for 5 weeks at 8°C. In Finland it is recommended that hot-smoked fish be stored at or below 3°C, further extending product safety. However, heating whitefish for 44 min at 85°C with 10% RH resulted in growth and toxicity in 5 weeks at 8°C. Moist heat thus enhanced spore thermal inactivation and is essential to an effective process. The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processes rainbow trout were observed.

AB - Thermal inactivation of nonproteolytic Clostridium botulinum type E spores was investigated in rainbow trout and whitefish media at 75 to 93°C. Lysozyme was applied in the recovery of spores, yielding biphasic thermal destruction curves. Approximately 0.1% of the spores were permeable to lysozyme, showing an increased measured heat resistance. Decimal reduction times for the heat-resistant spore fraction in rainbow trout medium were 255, 98, and 4.2 min at 75, 85, and 93°C, respectively, and those in whitefish medium were 55 and 7.1 min at 81 and 90°C, respectively. The z values were 10.4°C in trout medium and 10.1°C in whitefish medium. Commercial hot-smoking processes employed in five Finnish fish-smoking companies provided reduction in the numbers of spores of nonproteolytic C. botulinum of less than 103. An inoculated-pack study revealed that a time-temperature combination of 42 min at 85°C (fish surface temperature) with >70% relative humidity (RH) prevented growth from 106 spores in vacuum-packaged hot-smoked rainbow trout fillets and whole whitefish stored for 5 weeks at 8°C. In Finland it is recommended that hot-smoked fish be stored at or below 3°C, further extending product safety. However, heating whitefish for 44 min at 85°C with 10% RH resulted in growth and toxicity in 5 weeks at 8°C. Moist heat thus enhanced spore thermal inactivation and is essential to an effective process. The sensory qualities of safely processed and more lightly processed whitefish were similar, while differences between the sensory qualities of safely processed and lightly processes rainbow trout were observed.

U2 - 10.1128/AEM.69.7.4029-4036.2003

DO - 10.1128/AEM.69.7.4029-4036.2003

M3 - Article

VL - 69

SP - 4029

EP - 4036

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

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ER -