Isolation and identification of yeasts and filamentous fungi from yoghurts in Brazil

Abstract

Seventy-two cartons of yoghurt were sampled three times at monthly intervals from four different local manufacturers. Total counts were close to 6 x 10 7 cells g -1 of yoghurt. Yeast counts varied from 1 to 2,700 g -1 . There was no evidence of systematic contamination at source but this longitudinal study revealed that ad hoc contamination and improper storage led to the higher yeast counts. Contamination was generally higher in the hotter months but was lower overall than reported from other countries. A total of 577 yeast isolates were identified belonging to ten species. The most abundant yeasts were, in order, Debaryomyces hansenii, Saccharomyces cerevisiae, Mrakia frigida, Hansenula spp., Candida parapsilosis, Debaryomyces castellii and Candida maltosa. The psychrophilic yeast Mrakia frigida is reported for the first time in yoghurts. Low level contamination with Monilia and Penicillium species was found in a few samples. Growth tests suggested that ability to ferment sucrose, growth at 5ºC and in the presence of 300 µg g -1 sorbate preservative, were the three most significant physiological properties to account for these yeasts in yoghurts. The data also suggest that warmer weather and inadequate refrigeration are the principal causes of higher levels of contamination, increased diversity and change in microbial flora.

Yeast-like fungi isolated from indoor air in school buildings and the surrounding outdoor air

“…Food remains may also have been a source of and/or substrate for Debaryomyces occidentalis, D. hansenii or Mrakia frigida. Although they are used in biotechnology and the food industry (Mazurkiewicz-Zapałowicz 2006), they can also contaminate ready products (Moreira et al 2001).…”

Fungal contamination and chemical assessment of Iranian Doogh marketed in Hamadan, Iran

“…Mostly, among industrial Doogh samples, 32% of A samples were contaminated with molds and 64% of D samples were contaminated with yeasts. [16]. In addition, the presence of fungi in examined yoghurt samples was demonstrated by Eman et al that could be because of unsuitable preheating process during manufacturing and using undesirable sterilized plastic containers or inefficient cooling during storage [17].…”

Staphylococcus aureus and Methicillin Resistant S. aureus in Commercial Soft Drink with Antimicrobial Resistance Test on Isolates in Ethiopia

“…They are either energy drink, juice or water ready-todrink products getting popularity in food sectors [1]. They are produced and transported to a distance location to supply consumer under different handling conditions [2,3]. Risk of warmer weather condition and inadequate refrigeration were the principal causes of higher levels of contamination, increased diversity and change in microbial flora in the commercial product [2].…”

“…Risk of warmer weather condition and inadequate refrigeration were the principal causes of higher levels of contamination, increased diversity and change in microbial flora in the commercial product [2]. Range of spoilage microbial was reported from home-made tiger-nut beverages in Spain [3]. Abundant yeasts and fungi were isolated from yoghurts in Brazil [2].…”

“…The possible presences of some public health hazard microbial having most likely health threat in such processed products, including in the acidic products like juice, were also suggested, due to good acid-tolerance of such microbial [1][2][3][4][5]. Whether the products are produced by commercial or traditional methods, nonalcoholic beverages have risk of contamination with spoilage and public health pathogenic microbial [1][2][3][4][5][6][7][8].…”