Occurrence and ecological distribution of Heat Resistant Moulds Spores (HRMS) in raw materials used by food industry and thermal characterization of two Talaromyces isolates

Tranquillini, Roberta; Scaramuzza, N.; Berni, Elettra

doi:10.1016/j.ijfoodmicro.2016.11.023

Cited by 35 publications

(20 citation statements)

References 21 publications

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“…A direct comparison between our results and literature data was possible only with the paper by Tranquillini et al [34], where heatresistance of T. bacillisporus was assessed in the same heating medium, but using a culture medium not supplemented with tartaric acid for counting the survivors. In that case, the heat resistance of T. bacillisporus proved significantly lower at almost all the temperatures tested, except for 91°C where no difference was found using unacidified PDA.…”

Section: Thermal Resistance Studies On Talaromyces Bacillisporusmentioning

confidence: 77%

Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Responsible for Spoilage of Pasteurized Fruit Products

Sa¹,

Berni²

2017

J Food Process Technol

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The antimicrobial properties of chitosan, a deacetylated derivative of chitin, were assessed in a synthetic medium and in a blueberry and red grape juice against six heat resistant moulds (HRM) associated with food spoilage, in order to evaluate its use as a potential food preservative of natural origin. In both synthetic medium and natural substrate, the Minimum Inhibitory Concentration (MIC) of chitosan proved to vary in a wide range, regardless to both fungal genus and medium considered. Although Aspergillus neoglaber, Talaromyces bacillisporus and Aspergillus niger proved most resistant to chitosan (MIC > 5000 mg/L) on both media, a marked difference was detected for other strains tested. On HRM inoculated in MEB, the MIC was equal to 100 mg/L for Byssochlamys fulva or Monascus floridanus, and to 1000 mg/L for Talaromyces macrosporus. On HRM inoculated in blueberry and red grape juice, the MIC was equal to 2500 mg/L for Byssochlamys fulva or Monascus floridanus, and to 5000 mg/L for Talaromyces macrosporus.If combined with thermal treatment (80°C for 5 min) at a concentration (500 mg/L) that did not prove effective in inhibiting fungal spores, chitosan did not affect spore survival of microorganisms tested, thus allowing the spoilage of tested fruit juice after 5 days at 30°C. Also heat resistance parameters of a selected heat-resistant strain, T. bacillisporus, were not significantly affected by supplementation of blueberry and red grape juice with 500 mg/L of chitosan, D values ranging between 47.6 and 71.4 minutes at 82°C; 13.3 and 23.3 minutes at 85°C; 3.6 and 5.9 minutes at 88°C; 0.9 and 1.8 minutes at 91°C (z=5.2°C to 5.5°C). Since chitosan did not prove effective alone or combined with thermal treatment either to inactivate heat resistant microorganisms tested or to modify heat-resistance parameters of a heat resistant mould such as T. bacillisporus, its use cannot be considered as an interesting strategy to apply milder thermal treatments and to achieve stability of acid products. aim of this study was: (i) to assess the inhibiting and inactivating effect of chitosan on heat resistant Fungi, representing a matter of concern for manufacturers of pasteurized fruit products, and to test the synergistic effect of chitosan and thermal treatments on (ii) survival and (iii) heatresistance parameters of selected strains, to evaluate its possible use as a technological aid during the pasteurization of fruit-based products. Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Materials and Methods MicroorganismsThis study was carried out on different microbial strains:

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Section: Thermal Resistance Studies On Talaromyces Bacillisporusmentioning

confidence: 77%

Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Responsible for Spoilage of Pasteurized Fruit Products

Sa¹,

Berni²

2017

J Food Process Technol

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“…Talaromyces trachyspermus causes the spoilage of apple juice, heat‐processed pineapple products, canned strawberries and tea‐based beverages, and has also been isolated from raw materials used to produce pasteurized fruit‐based products (Pitt and Hocking ; Tranquillini et al . ). These fungi are known to produce several types of mycotoxins, including duclauxin and spiculisporic acid (Frisvad et al .…”

Section: Introductionmentioning

confidence: 97%

Design of a species-specific PCR method for the detection of the heat-resistant fungi Talaromyces macrosporus and Talaromyces trachyspermus

Yamashita

Nakagawa²,

Sakaguchi

et al. 2017

Lett Appl Microbiol

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Significance and Impact of the Study: Polymerase chain reaction (PCR)-based detection is rapid, convenient and sensitive compared with traditional methods of detecting heat-resistant fungi. In this study, a PCR-based method was developed for the detection and identification of amplification products from Talaromyces macrosporus and Talaromyces trachyspermus using primer sets that target the isocitrate lyase gene. This method could be used for the on-site detection of T. macrosporus and T. trachyspermus in the near future, and will be helpful in the safety control of raw materials and in food and beverage production. AbstractHeat-resistant fungi occur sporadically and are a continuing problem for the food and beverage industry. The genus Talaromyces, as a typical fungus, is capable of producing the heat-resistant ascospores responsible for the spoilage of processed food products. Isocitrate lyase, a signature enzyme of the glyoxylate cycle, is required for the metabolism of non-fermentable carbon compounds, like acetate and ethanol. Here, species-specific primer sets for detection and identification of DNA derived from Talaromyces macrosporus and Talaromyces trachyspermus were designed based on the nucleotide sequences of their isocitrate lyase genes. Polymerase chain reaction (PCR) using a species-specific primer set amplified products specific to T. macrosporus and T. trachyspermus. Other fungal species, such as Byssochlamys fulva and Hamigera striata, which cause food spoilage, were not detected using the Talaromyces-specific primer sets. The detection limit for each species-specific primer set was determined as being 50 pg of template DNA, without using a nested PCR method. The specificity of each species-specific primer set was maintained in the presence of 1,000-fold amounts of genomic DNA from other fungi. The method also detected fungal DNA extracted from blueberry inoculated with T. macrosporus. This PCR method provides a quick, simple, powerful and reliable way to detect T. macrosporus and T. trachyspermus.

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“…Talaromyces macrosporus, which is a heat-resistant fungus that can induce spoilage of pasteurized food products, has been used as a model organism for studying the heat resistance and activation of ascospores (Dijksterhuis et al 2002;Kikoku 2003). Talaromyces trachyspermus has been isolated from heat-processed cheeses, canned strawberries, tea-based beverages and raw materials used in the food industry (Pitt and Hocking 2009;Tranquillini et al 2017). These fungi are able to produce several types of mycotoxins, including duclauxin and spiculisporic acid (Frisvad et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Detection of Talaromyces macrosporus and Talaromyces trachyspermus by a PCR assay targeting the hydrophobin gene

Yamashita

Nakagawa²,

Sakaguchi

et al. 2019

Lett Appl Microbiol

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Talaromyces species are typical fungi capable of producing the heat‐resistant ascospores responsible for the spoilage of processed food products. Hydrophobins, which are unique to fungi, are small secreted proteins that form amphipathic layers on the outer surface of fungal cell walls. In this study, species‐specific primer sets for detecting and identifying Talaromyces macrosporus and Talaromyces trachyspermus were designed based on hydrophobin gene sequences. A conventional polymerase chain reaction (PCR) assay using these primer sets produced species‐specific amplicons for T. macrosporus and T. trachyspermus. The detection limit for each primer set was 100 pg template DNA. This assay also detected fungal DNA extracted from blueberries inoculated with T. macrosporus. Other heat‐resistant fungi, including Byssochlamys, Neosartorya and Talaromyces species, which cause food spoilage, were not detected in PCR amplifications with these primer sets. Furthermore, a conventional PCR assay using a crude DNA extract as the template also yielded amplicons specific to T. macrosporus and T. trachyspermus. The simple and rapid PCR assay described herein is highly species‐specific and can reliably detect T. macrosporus and T. trachyspermus, suggesting it may be relevant for the food and beverage industry. Significance and Impact of the Study The heat‐resistant ascospores of Talaromyces macrosporus and Talaromyces trachyspermus are responsible for food spoilage after pasteurization. Traditional methods for detecting fungal contamination based on morphological characteristics are time‐consuming and exhibit low sensitivity and specificity. In this study, a conventional polymerase chain reaction (PCR) assay based on hydrophobin gene sequences was developed for the specific detection of T. macrosporus and T. trachyspermus. This detection method was simple, rapid and highly specific. These results suggest that the conventional PCR assay developed in this study may be useful for detecting T. macrosporus and T. trachyspermus in raw materials and processed food products.

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Occurrence and ecological distribution of Heat Resistant Moulds Spores (HRMS) in raw materials used by food industry and thermal characterization of two Talaromyces isolates

Cited by 35 publications

References 21 publications

Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Responsible for Spoilage of Pasteurized Fruit Products

Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Responsible for Spoilage of Pasteurized Fruit Products

Design of a species-specific PCR method for the detection of the heat-resistant fungi Talaromyces macrosporus and Talaromyces trachyspermus

Detection of Talaromyces macrosporus and Talaromyces trachyspermus by a PCR assay targeting the hydrophobin gene

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