Protective effect of the use of bioprotective culture in kefir production against Escherichia coli and Enterococcus faecalis contamination
Küçük Resim Yok
Tarih
2024
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The present study aimed to assess the effect of bioprotective lactic acid bacteria, known for enhancing food shelf life and possessing inherent protective traits, on the contamination of kefir production by Escherichia coli and Enterococcus faecalis. In addition to the standard kefir starter culture, commercial protective cultures of Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Propionibacterium freudenreichii subsp. shermanii were employed, and their effects were scrutinized. The control group kefirs (EC-FR) underwent no supplementation beyond the starter culture. The kefirs produced were stored at 4 °C for 21 days, with analyses conducted on the 1st, 7th, 14th, and 21st days to assess the effect of protective cultures on target bacteria (Escherichia coli and Enterococcus faecalis), starter bacteria in the kefir culture, and yeast and mold counts. Throughout storage, pH levels ranged from 4.27 to 4.46. Examination of Escherichia coli counts in kefir samples revealed that while the presence of this bacterium ceased in samples with ER, ES, and EP protective cultures by the 14th day, the most significant effect among protective cultures was observed in kefir utilizing Lacticaseibacillus rhamnosus (ER) by day 7. Kefir samples contaminated with Enterococcus faecalis exhibited pH levels between 4.27 and 4.46 during storage. Although Enterococcus faecalis was not completely inhibited during storage, the protective culture most effectively reduced its count compared to the control group, which was Lacticaseibacillus rhamnosus (FR). Given the proximity of pH values, protective cultures are presumed to provide protection effectively. Consequently, the inhibitory property was demonstrated in kefirs contaminated with 0.1% Escherichia coli and Enterococcus faecalis in kefirs produced using protective cultures, with Lacticaseibacillus rhamnosus (ER-FR) exhibiting the most significant effect. Lower bacterial counts of contamination were observed in kefirs utilizing Propionibacterium freudenreichii subsp. shermanii compared to control kefirs, thus affirming its protective attribute. © 2024 Elsevier Ltd
Açıklama
Anahtar Kelimeler
Contamination, Kefir, Natural preservative cultures, Shelf life
Kaynak
Food Bioscience
WoS Q Değeri
Scopus Q Değeri
Q1
Cilt
61
