Yahya Almutawif1,2,3, Benjamin Hartmann4,5,6, Megan Lloyd2,3,6,7, Ching Tat Lai8, Alethea Rea9, Donna Geddes8. 1. 1 Department of Medical Laboratory Technology, College of Applied Medical Sciences, Taibah University, Madinah, Saudi Arabia. 2. 2 School of Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Crawley, Australia. 3. 3 Marshall Center for Infectious Diseases Research and Training, The University of Western Australia, Crawley, Australia. 4. 4 Perron Rotary Express Milk Bank, King Edward Memorial Hospital, Subiaco, Australia. 5. 5 Center for Neonatal Research and Education, The University of Western Australia, Crawley, Australia. 6. 6 School of Paediatrics, Faculty of Health and Medical Sciences, The University of Western Australia, Crawley, Australia. 7. 7 School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia. 8. 8 School of Molecular Sciences, Faculty of Science, The University of Western Australia, Crawley, Australia. 9. 9 Center for Applied Statistics, The University of Western Australia, Crawley, Australia.
Abstract
Background: Some strains of Staphylococcus aureus can produce heat-stable enterotoxins that have been associated with gastritis and potentially necrotizing enterocolitis in preterm infants. Objectives/Hypothesis: To assess the impact of different storage temperatures on S. aureus growth and enterotoxin production in raw, Holder-pasteurized (HP) and ultraviolet-C (UV-C)-treated donated human milk (DHM). Materials and Methods: The milk samples from individual donors were pooled and divided into four equal portions. One portion was HP, the second was UV-C treated, the third was not treated, and the fourth was UV-C treated after being spiked with S. aureus. All samples were incubated at 37°C (18 hours) and 4°C (14 days). Bacterial colony count, enterotoxin A and B, and immune proteins were quantified. Results: At 37°C, the colony count increased in HP DHM and decreased in raw and UV-C-treated DHM. At 4°C, colony counts in HP DHM reduced and were not detected in raw and UV-C-treated DHM from day 8 of incubation. No bacteria were detected in samples that were inoculated before UV-C treatment. Enterotoxin A was only detected in HP-DHM at 37°C from the 9th hour onward. Enterotoxin B was detected in one sample at the 15th hour. Immune protein concentrations were similar in raw and UV-C DHM, and were reduced in the HP DHM. Conclusion: UV-C-treated milk reduces S. aureus growth with similar kinetics to raw milk making it a promising emerging technique to eliminate bacteria while retaining essential immune proteins in DHM.
Background: Some strains of Staphylococcus aureus can produce heat-stable enterotoxins that have been associated with gastritis and potentially necrotizing enterocolitis in preterm infants. Objectives/Hypothesis: To assess the impact of different storage temperatures on S. aureus growth and enterotoxin production in raw, Holder-pasteurized (HP) and ultraviolet-C (UV-C)-treated donated human milk (DHM). Materials and Methods: The milk samples from individual donors were pooled and divided into four equal portions. One portion was HP, the second was UV-C treated, the third was not treated, and the fourth was UV-C treated after being spiked with S. aureus. All samples were incubated at 37°C (18 hours) and 4°C (14 days). Bacterial colony count, enterotoxin A and B, and immune proteins were quantified. Results: At 37°C, the colony count increased in HP DHM and decreased in raw and UV-C-treated DHM. At 4°C, colony counts in HP DHM reduced and were not detected in raw and UV-C-treated DHM from day 8 of incubation. No bacteria were detected in samples that were inoculated before UV-C treatment. Enterotoxin A was only detected in HP-DHM at 37°C from the 9th hour onward. Enterotoxin B was detected in one sample at the 15th hour. Immune protein concentrations were similar in raw and UV-C DHM, and were reduced in the HP DHM. Conclusion: UV-C-treated milk reduces S. aureus growth with similar kinetics to raw milk making it a promising emerging technique to eliminate bacteria while retaining essential immune proteins in DHM.
Entities:
Keywords:
Holder pasteurization; UV-C treatment; donated human milk; enterotoxin
Authors: Jéssica Bomfim de Almeida; Suzi Pacheco de Carvalho; Lucas S C da Silva; Yasmin M F S Andrade; Raiane Cardoso Chamon; Kátia Regina Netto Dos Santos; Lucas M Marques Journal: Braz J Microbiol Date: 2020-08-21 Impact factor: 2.476