The Effect of Thermal Pasteurization, Freeze-Drying, and Gamma Irradiation on Donor Human Milk

The most common pasteurisation method used by human milk banks is Holder pasteurisation. This involves thermal processing, which can denature important proteins and can potentially reduce the natural antimicrobial properties found in human milk. This study assesses the application of a hybrid method comprised of freeze-drying followed by low-dose gamma-irradiation for nonthermal donor human milk pasteurisation. Freeze-drying donor human milk followed by gamma-irradiation at 2 kGy was as efficient as Holder pasteurisation in the reduction of bacterial inoculants of Staphylococcus aureus (106 cfu/mL) and Salmonella typhimurium (106 cfu/mL) in growth inhibition assays. These assays also demonstrated that human milk naturally inhibits the growth of bacterial inoculants S. aureus, S. typhimurium, and Escherichia coli. Freeze drying (without gamma-irradiation) did not significantly reduce this natural growth inhibition. By contrast, Holder pasteurisation significantly reduced the milk’s natural antimicrobial effect on S. aureus growth after 6 h (−19.8% p = 0.01). Freeze-dried and then gamma-irradiated donor human milk showed a strong antimicrobial effect across a dose range of 2–50 kGy, with only a minimal growth of S. aureus observed after 6 h incubation. Thus, a hybrid method of freeze-drying followed by 2 kGy of gamma-irradiation preserves antimicrobial properties and enables bulk pasteurisation within sealed packaging of powderised donor human milk. This work forwards a goal of increasing shelf life and simplifying storage and transportation, while also preserving functionality and antimicrobial properties.

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Quality study of Holder pasteurization of donor human milk in a neonatal personalized nutrition unit

Anales de Pediatría (English Edition) ◽

10.1016/j.anpede.2021.06.002 ◽

2021 ◽

Author(s):

Sylvia Caballero Martín ◽

Maria del Carmen Sánchez Gómez de Orgaz ◽

Manuel Sánchez Luna

Keyword(s):

Human Milk ◽

Personalized Nutrition ◽

Donor Human Milk ◽

Quality Study

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High-Temperature Short-Time and Holder Pasteurization of Donor Milk: Impact on Milk Composition

Life ◽

10.3390/life11020114 ◽

2021 ◽

Vol 11 (2) ◽

pp. 114

Author(s):

Diana Escuder-Vieco ◽

Juan M. Rodríguez ◽

Irene Espinosa-Martos ◽

Nieves Corzo ◽

Antonia Montilla ◽

...

Keyword(s):

High Temperature ◽

Human Milk ◽

Milk Composition ◽

Donor Human Milk ◽

High Temperature Short Time ◽

Lactose Concentration ◽

C 30 ◽

Milk Banks ◽

Short Time

Holder pasteurization (HoP; 62.5 °C, 30 min) is commonly used to ensure the microbiological safety of donor human milk (DHM) but diminishes its nutritional properties. A high-temperature short-time (HTST) system was designed as an alternative for human milk banks. The objective of this study was to evaluate the effect of this HTST system on different nutrients and the bile salt stimulated lipase (BSSL) activity of DHM. DHM was processed in the HTST system and by standard HoP. Macronutrients were measured with a mid-infrared analyzer. Lactose, glucose, myo-inositol, vitamins and lipids were assayed using chromatographic techniques. BSSL activity was determined using a kit. The duration of HTST treatment had a greater influence on the nutrient composition of DHM than did the tested temperature. The lactose concentration and the percentage of phospholipids and PUFAs were higher in HTST-treated than in raw DHM, while the fat concentration and the percentage of monoacylglycerides and SFAs were lower. Other nutrients did not change after HTST processing. The retained BSSL activity was higher after short HTST treatment than that following HoP. Overall, HTST treatment resulted in better preservation of the nutritional quality of DHM than HoP because relevant thermosensitive components (phospholipids, PUFAs, and BSSL) were less affected.

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The Current State of Donor Human Milk Use and Practice

Journal of Midwifery & Women s Health ◽

10.1111/jmwh.13244 ◽

2021 ◽

Author(s):

Yeon Bai ◽

Jennifer Kuscin

Keyword(s):

Human Milk ◽

Donor Human Milk ◽

Current State

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New Operating Approach to Limit Bacillus Cereus Contamination of Donor Human Milk

Journal of Human Lactation ◽

10.1177/08903344211002563 ◽

2021 ◽

pp. 089033442110025

Author(s):

Domenica Mallardi ◽

Pasqua Piemontese ◽

Nadia Liotto ◽

Rosaria M. Colombo ◽

Antonella Dodaro ◽

...

Keyword(s):

Human Milk ◽

Bacillus Cereus ◽

Donor Human Milk

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Inactivation of Bacterial Pathogens in Human Milk by High-Pressure Processing†

Journal of Food Protection ◽

10.4315/0362-028x-71.1.109 ◽

2008 ◽

Vol 71 (1) ◽

pp. 109-118 ◽

Cited By ~ 39

Author(s):

S. VIAZIS ◽

B. E. FARKAS ◽

L. A. JAYKUS

Keyword(s):

High Pressure ◽

Human Milk ◽

Capillary Tube ◽

Bacterial Pathogens ◽

High Pressure Processing ◽

Viral Pathogens ◽

Promising Alternative ◽

Log Reduction ◽

Long Time ◽

Thermal Pasteurization

Low-temperature, long-time (LTLT) pasteurization assures the safety of banked human milk; however, heat can destroy important nutritional biomolecules. High-pressure processing (HPP) shows promise as an alternative for pasteurization of breast milk. The purpose of this study was to investigate the efficacy of HPP for inactivation of selected bacterial pathogens in human milk. Human milk was inoculated with one of five pathogens (108 to 109 CFU/ml), while 0.1% peptone solution solutions with the same levels of each organism were used as controls. The samples were subjected to 400 MPa at 21 to 31°C for 0 to 50 min or to 62.5°C for 0 to 30 min (capillary tube method) to simulate LTLT pasteurization. Tryptic soy agar and selective media were used for enumeration. Traditional thermal pasteurization resulted in inactivation (>7 log) of all pathogens within 10 min. In human milk and in peptone solution, a 6-log reduction was achieved after 30 min of HPP for Staphylococcus aureus ATCC 6538. After 30 min, S. aureus ATCC 25923 was reduced by 8 log and 6 log in human milk and peptone solution, respectively. Treatments of 4 and 7 min resulted in an 8-log inactivation of Streptococcus agalactiae ATCC 12927 in human milk and peptone solution, respectively, while Listeria monocytogenes ATCC 19115 required 2 min for an 8-log inactivation in human milk. Escherichia coli ATCC 25922 was inactivated by 8 log after 10 min in peptone solution and by 6 log after 30 min in human milk. These data suggest that HPP may be a promising alternative for pasteurization of human milk. Further research should evaluate the efficacy of HPP in the inactivation of relevant viral pathogens.

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