Alicyclobacillus

Alicyclobacillus
Scientific classification
Domain: Bacteria
Division: Firmicutes
Class: Bacilli
Order: Bacillales
Family: Alicyclobacillaceae
Genus: Alicyclobacillus
Wisotzkey 1992
Species

A. acidiphilus
A. acidocaldarius
A. acidocaldarius subsp. acidocaldarius
A. acidocaldarius subsp. rittmannii
A. acidoterrestris
A. aeris
A. contaminans
A. cycloheptanicus
A. disulfidooxidans
A. fastidiosus
A. ferrooxydans
A. herbarius
A. hesperidum
A. kakegawensis
A. macrosporangiidus
A. pohliae
A. pomorum
A. sacchari
A. sendaiensis
A. shizuokensis
A. tolerans
A. vulcanalis

Alicyclobacillus is a genus of Gram-positive, rod-shaped, spore-forming bacteria. The bacteria are able to grow in acidic conditions, while the spores are able to survive typical pasteurization procedures.

Overview

Alicyclobacilli are strictly aerobic, acidophilic, thermophilic, soil-dwelling organisms, and have been shown to grow at temperatures between 20 and 70 °C (with the optimum temperature range being 42–60 °C) and pH values of 2.0 to 6.0.[1] Alicyclobacilli are of special interest to the fruit juice canning industry because common pasteurization techniques (92 °C for 10 seconds) do not deactivate the spores;[2] Alicyclobacillus species can have a D-value of over 8 minutes (requiring treatment of over 8 minutes at 95 °C to kill 90% of spores).[3] When a product is spoiled by Alicyclobacillus, the juice products develop a disinfectant-like odor and/or flavor (due to guaiacol production), but the bacteria do not cause swelling of the package or discoloration of the product,[4] nor is it pathogenic to humans.[5] Alicyclobacilli have been implicated in spoilages of pear, orange, peach, mango, and white grape juice, fruit juice blends, and tomato products.[6] Not all Alicyclobacilli produce guaiacol, and thus not all species are of spoilage concern.[7]

Background

The first Alicyclobacillus species was isolated in 1967 from hot springs, and was named Bacillus acidocaldarius. However, it was not until 1982 that the organisms were implicated in the spoilage of apple juice. The next outbreak occurred in 1994, and based on 16S rRNA studies, a separate genus was proposed.[4] A. acidoterrestris is considered the most important spoilage species within the Alicyclobacillus genus,[8] but A. acidocaldarius, A. pomorum, and A. herbarius have also been isolated from spoiled product.[9]

Impact

The canning industry works under the assumption that bacterial spores will not germinate at pH values below 4.6, and that acid-tolerant organisms are not very heat resistant. In this case, a low heat pasteurization process is applicable. However, the emergence of Alicyclobacillus as a spoilage organism has led some researchers to advocate using A. acidoterrestris as the reference organism to design pasteurization processes for high acid foods, just as the thermal death time of Clostridium botulinum was used to design the sterilization process for low acid canned foods.[10] High-pressure processing has been shown to be effective at inactivating A. acidoterrestris spores in orange juice.[11] One survey of 8556 samples of fruit and vegetable juices found Alicyclobacillus in 13% of samples,[12] while another study found Alicyclobacillus in 6% out of 180 samples,[13] and another found the bacteria in 14% out of 75 samples.[3]

In The Netherlands in 2013, contamination of raspberry with Alicyclobacillus in pasteurized juices led to a public recall after consumers complained about bad taste and odor.[14]

References

  1. ↑ Su-Sen Chang and Dong-Hyun Kang. Alicyclobacillus spp. in the Fruit Juice Industry: History, Characteristics, and Current Isolation/Detection Procedures. Critical Reviews in Microbiology, 30:55–74, 2004.
  2. ↑ Alicyclobacillus, the Beverage Industry and the BioSys Rapid Microbiology. Retrieved 2010-12-22
  3. 1 2 M.N.U. Eiroa, V.C.A. Junqueira, F.L. Schimdt. Alicyclobacillus in orange juice: occurrence and heat resistance of spores. Journal of Food Protection, 62 (8) (1999), pp. 883–886.
  4. 1 2 Eiroa, Mirtha Nelly Uboldi, Junqueira, Valéria Christina Amstalden, Schmidt, Flaávio. Alicyclobacillus in Orange Juice: Occurrence and Heat Resistance of Spores. Journal of Food Protection, Volume 62, Number 8, August 1999 , pp. 883-886(4)
  5. ↑ Filipa V. M. Silva and Paul Gibbs. Alicyclobacillus acidoterrestris spores in fruit products and design of pasteurization processes. Trends in Food Science & Technology, Volume 12, Issue 2, February 2001, Pages 68-74.
  6. ↑ Willem H. Groenewald, Pieter A. Gouws and R. Corli Witthuhn. Isolation, identification and typification of Alicyclobacillus acidoterrestris and Alicyclobacillus acidocaldarius strains from orchard soil and the fruit processing environment in South Africa. Food Microbiology. Volume 26, Issue 1, February 2009, Pages 71-76.
  7. ↑ S.S. Changa, S.H. Parkb, D.H. Kang. Development of novel agar media for isolating guaiacol producing Alicyclobacillus spp. International Journal of Food Microbiology. Volume 164, Issue 1, 3 June 2013, Pages 1–6.
  8. ↑ Ana Cláudia N. F. Spinelli, Anderson S. Sant'Ana, Salatir Rodrigues-Junior, and Pilar R. Massaguer. Influence of Different Filling, Cooling, and Storage Conditions on the Growth of Alicyclobacillus acidoterrestris CRA7152 in Orange Juice. Applied and Environmental Microbiology, December 2009, p. 7409-7416, Vol. 75, No. 23
  9. ↑ I.C. McKnight, M.N.U. Eiroa, A.S. Sant'Ana, and P.R. Massaguer. Alicyclobacillus acidoterrestris in pasteurized exotic Brazilian fruit juices: Isolation, genotypic characterization and heat resistance. Food Microbiology. Volume 27, Issue 8, December 2010, Pages 1016-1022.
  10. ↑ Filipa V. M. Silva, Paul Gibbs. Target Selection in Designing Pasteurization Processes for Shelf-Stable High-Acid Fruit Products. Critical Reviews in Food Science and Nutrition, Volume 44, Issue 5, 2004, pages 353-360.
  11. ↑ Filipa V.M. Silva, Eng Keat Tan, Mohammed Farid. Bacterial spore inactivation at 45–65°C using high pressure processing: Study of Alicyclobacillus acidoterrestris in orange juice. Food Microbiology. Volume 32, Issue 1, October 2012, Pages 206–211.
  12. ↑ J.M. Oteiza, G. Ares, A.S. Sant'Ana, S. Soto, L. Giannuzzi Use of a multivariate approach to assess the incidence of Alicyclobacillus spp. in concentrate fruit juices marketed in Argentina: results of a 14-year survey. International Journal of Food Microbiology 151 (2) (2011), pp. 229–234
  13. ↑ M.D. Danyluk, L.M. Friedrich, C. Jouquand, R. Goodrich-Schneider, M.E. Parish, R. Rouseff. Prevalence, concentration, spoilage, and mitigation of Alicyclobacillus spp. in tropical and subtropical fruit juice concentrates. Food Microbiology, 28 (3) (2011), pp. 472–477
  14. ↑ Graanoogst, Audrey. (2013-09-19) Contaminated fruit juice Wicky recalled. NLTimes.nl. Retrieved 2014-05-03.
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