The population change of yeasts in commercial salami

Aims: To characterize micro-organisms isolated from Norwegian dairy production plants after cleaning and fogging disinfection with alkyl amine/peracetic acid and to indicate reasons for survival. Methods and Results: Microbial samples were collected from five dairy plants after cleaning and fogging disinfection. Isolates from two of these production plants, which used fogging with alkylamino acetate (plant A), and peracetic acid (plant B), were chosen for further characterization. The sequence of the 16S ribosomal DNA, fatty acid analysis and biochemical characteristics were used to identify isolates. Three isolates identified as Rhodococcus erythropolis, Methylobacterium rhodesianum and Rhodotorula mucilaginosa were isolated from plant A and one Sphingomonas sp. and two M. extorquens from plant B. Different patterns of resistance to seven disinfectants in a bactericidal suspension test and variable degree of attachment to stainless steel were found. The strains with higher disinfectant resistance showed lower degree of attachment than susceptible strains. Conclusions: The study identifies and characterizes micro-organisms present after cleaning and fogging disinfection. Both surface attachment and resistance were shown as possible reasons for the presence of the isolates after cleaning and disinfection. Significance and Impact of the Study: These results contribute to the awareness of disinfectant resistance as well as attachment as mechanisms of survival in dairy industry. It also strengthens the argument of frequent alternation of disinfectants in the food processing industry to avoid the establishment of resistant house strains.

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“…2001), juice (Shearer et al. 2002), salami (Abunyewa et al. 2000) and intermediate moisture meats (Wolter et al.…”

Section: Discussionmentioning

confidence: 99%

Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acid

Bore

Langsrud²

2005

J Appl Microbiol

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“…Yarrowia lipolytica has been detected in salami (Abunyewa et al, 2000;Gardini et al, 2001;Gianni et al, 2008;Nielsen et al, 2008), Spanish fermented sausages such as chorizo, longaniza and salchichon (Encinas et al, 2000;Martinez et al, 2004), German (dry fermented) sausages such as Zervelat and Frankfurters (Entel, 1961;Samelis & Sofos, 2003), as well as in Vienna, tea and other sausages (Leistner & Bem, 1970;Viljoen et al, 1993;Zivanovic & Ristic, 1974). The prevalence of Y. lipolytica was higher at the surface than in the interior of the products (Leistner & Bem, 1970).…”

Section: Natural Occurrence Of Yarrowia Lipolytica In Foodmentioning

confidence: 99%

“…The prevalence of Y. lipolytica was higher at the surface than in the interior of the products (Leistner & Bem, 1970). Yarrowia lipolytica has also been reported to occur in ham (Fung & Liang, 1990;Leistner & Bem, 1970), salted bacon (Nielsen et al, 2008), beef (Aboukheir & Kilbertus, 1974;Fung & Liang, 1990), poultry (Ismail et al, 2000;Sinigaglia et al, 1994;Viljoen et al, 1998), biltong (Wolter et al, 2000), other meat samples (Abunyewa et al, 2000;Fleet, 1992;Martinez et al, 2004) and -occasionally -also in fish (Oliveira Leme et al, 2011;Ross & Morris, 1965). As a caveat, Y. lipolytica and Candida alimentaria, a recently identified member of the Yarrowia clade (Knutsen et al, 2007), were found to co-exist in processed meat products (Nielsen et al, 2008); thus, it may be hypothesized that some of the earlier identifications of Y. lipolytica in meat might actually relate to C. alimentaria.…”

Section: Natural Occurrence Of Yarrowia Lipolytica In Foodmentioning

confidence: 99%

Yarrowia lipolytica: Safety assessment of an oleaginous yeast with a great industrial potential

Groenewald

Boekhout

Neuvéglise

et al. 2013

Critical Reviews in Microbiology

384

288

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Yarrowia lipolytica has been developed as a production host for a large variety of biotechnological applications. Efficacy and safety studies have demonstrated the safe use of Yarrowia-derived products containing significant proportions of Yarrowia biomass (as for DuPont's eicosapentaenoic acid-rich oil) or with the yeast itself as the final product (as for British Petroleum's single-cell protein product). The natural occurrence of the species in food, particularly cheese, other dairy products and meat, is a further argument supporting its safety. The species causes rare opportunistic infections in severely immunocompromised or otherwise seriously ill people with other underlying diseases or conditions. The infections can be treated effectively by the use of regular antifungal drugs, and in some cases even disappeared spontaneously. Based on our assessment, we conclude that Y. lipolytica is a ''safe-to-use'' organism.

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“…Debaryomyces hansenii and Candida zeylanoides are two of the most frequently isolated yeast species from meat products (10), probably due to the fact that they are both tolerant to low temperatures and high salt concentrations (9,24,35). At present, it is not known how the growth and physiology of these two yeast species are affected by acidified nitrite.…”

Section: Nitrite (Nomentioning

confidence: 99%

Intracellular pH Homeostasis Plays a Role in the Tolerance of Debaryomyces hansenii and Candida zeylanoides to Acidified Nitrite

Mortensen

Jacobsen

Koch

et al. 2008

Appl Environ Microbiol

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The effects of acidified-nitrite stress on the growth initiation and intracellular pH (pH i ) of individual cells of Debaryomyces hansenii and Candida zeylanoides were investigated. Our results show that 200 g/ml of nitrite caused pronounced growth inhibition and intracellular acidification of D. hansenii at an external pH (pH ex ) value of 4.5 but did not at pH ex 5.5. These results indicate that nitrous acid as such plays an important role in the antifungal effect of acidified nitrite. Furthermore, both yeast species experienced severe growth inhibition and a pH i decrease at pH ex 4.5, suggesting that at least some of the antifungal effects of acidified nitrite may be due to intracellular acidification. For C. zeylanoides, this phenomenon could be explained in part by the uncoupling effect of energy generation from growth. Debaryomyces hansenii was more tolerant to acidified nitrite at pH ex 5.5 than C. zeylanoides, as determined by the rate of growth initiation. In combination with the fact that D. hansenii was able to maintain pH i homeostasis at pH ex 5.5 but C. zeylanoides was not, our results suggest that the ability to maintain pH i homeostasis plays a role in the acidified-nitrite tolerance of D. hansenii and C. zeylanoides. Possible mechanisms underlying the different abilities of the two yeast species to maintain their pH i homeostasis during acidified-nitrite stress, comprising the intracellular buffer capacity and the plasma membrane ATPase activity, were investigated, but none of these mechanisms could explain the difference.

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The population change of yeasts in commercial salami

Cited by 29 publications

References 26 publications

Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acid

Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acid

Yarrowia lipolytica: Safety assessment of an oleaginous yeast with a great industrial potential

Intracellular pH Homeostasis Plays a Role in the Tolerance of Debaryomyces hansenii and Candida zeylanoides to Acidified Nitrite

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