Presence of Bacillus species in pasteurised milk and their phenotypic and genotypic antimicrobial resistance profile

Abstract

High‐temperature short‐time (HTST) pasteurisation is not sufficient for complete elimination of Bacillus sp. in milk. Hence, it is important to assess their prevalence, phenotypic and genetic antimicrobial resistance profiles in pasteurised milk. In this study, we investigated Bacillus prevalence and their phenotypic resistance to 25 antimicrobials and prevalence of five plasmid antimicrobial resistance genes. All isolates were resistant to β‐lactams; most isolates were susceptible to chloramphenicol (n = 52), ciprofloxacin, meropenem, sulphonamides, tetracycline and vancomycin (n = 56). Intriguingly, despite phenotypic sulphonamide and tetracycline sensitivity, Sul2 and tetA genes were detected in different Bacillus species, signifying a potential risk of horizontal gene transfer of these mobile resistance genes through pasteurised milk.

Lactoferrin's potential application in enhancing yoghurt's microbial and sensory qualities, with emphasis on the starter culture activity

“…In the United Kingdom, there were an estimated 2.4 million instances of food-borne gastroenteritis in 2018, with 16 300 cases requiring hospitalization and more than 180 deaths (Jenkins et al ., 2022). S. aureus, E. coli, Salmonella species, and B. cereus are the most prevalent microorganisms isolated in the previous studies (Abdel-Salam and Soliman, 2019; Atia et al ., 2020; Adam et al ., 2021; Halim et al ., 2022; Taher et al ., 2022; Nadi et al ., 2023). In addition, P. aeruginosa is the leading cause of spoiled dairy products; it releases thermo-tolerant proteolytic and lipolytic enzymes that impact dairy product quality and shelf life (Eleboudy et al ., 2015; Ahmed et al ., 2021).…”