Inactivation of Bacillus cereus spores using a combined treatment of UV-TiO2 photocatalysis and high hydrostatic pressure

Breast milk is the nutritional reference for the child and especially for the preterm infant. Breast milk is better than donated breast milk (DHM), but if breast milk is not available, DHM is distributed by the Human Milk Bank (HMB). Raw Human Milk is better than HMB milk, but it may contain dangerous germs, so it is usually milk pasteurized by a Holder treatment (62.5 °C 30 min). However, Holder does not destroy all germs, and in particular, in 7% to 14%, the spores of Bacillus cereus are found, and it also destroys the microbiota, lipase BSSL and immune proteins. Another technique, High-Temperature Short Time (HTST 72 °C, 5–15 s), has been tried, which is imperfect, does not destroy Bacillus cereus, but degrades the lipase and partially the immune proteins. Therefore, techniques that do not treat by temperature have been proposed. For more than 25 years, high hydrostatic pressure has been tried with pressures from 100 to 800 MPa. Pressures above 400 MPa can alter the immune proteins without destroying the Bacillus cereus. We propose a High Hydrostatic Pressure (HHP) with four pressure cycles ranging from 50–150 MPa to promote Bacillus cereus germination and a 350 MPa Pressure that destroys 106 Bacillus cereus and retains 80–100% of lipase, lysozyme, lactoferrin and 64% of IgAs. Other HHP techniques are being tested. We propose a literature review of these techniques.

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Inactivation of Escherichia coli andListeria innocua in Milk by Combined Treatment with High Hydrostatic Pressure and the Lactoperoxidase System

Applied and Environmental Microbiology ◽

10.1128/aem.66.10.4173-4179.2000 ◽

2000 ◽

Vol 66 (10) ◽

pp. 4173-4179 ◽

Cited By ~ 63

Author(s):

Cristina García-Graells ◽

Caroline Valckx ◽

Chris W. Michiels

Keyword(s):

Escherichia Coli ◽

High Pressure ◽

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Combined Treatment ◽

Food Preservation ◽

Pressure Treatment ◽

E Coli ◽

Preservation Method ◽

Lactoperoxidase System

ABSTRACT We have studied inactivation of four strains each ofEscherichia coli and Listeria innocua in milk by the combined use of high hydrostatic pressure and the lactoperoxidase-thiocyanate-hydrogen peroxide system as a potential mild food preservation method. The lactoperoxidase system alone exerted a bacteriostatic effect on both species for at least 24 h at room temperature, but none of the strains was inactivated. Upon high-pressure treatment in the presence of the lactoperoxidase system, different results were obtained for E. coli and L. innocua. For none of the E. coli strains did the lactoperoxidase system increase the inactivation compared to a treatment with high pressure alone. However, a strong synergistic interaction of both treatments was observed for L. innocua. Inactivation exceeding 7 decades was achieved for all strains with a mild treatment (400 MPa, 15 min, 20°C), which in the absence of the lactoperoxidase system caused only 2 to 5 decades of inactivation depending on the strain. Milk as a substrate was found to have a considerable effect protecting E. coli and L. innocua against pressure inactivation and reducing the effectiveness of the lactoperoxidase system under pressure on L. innocua. Time course experiments showed that L. innocua counts continued to decrease in the first hours after pressure treatment in the presence of the lactoperoxidase system.E. coli counts remained constant for at least 24 h, except after treatment at the highest pressure level (600 MPa, 15 min, 20°C), in which case, in the presence of the lactoperoxidase system, a transient decrease was observed, indicating sublethal injury rather than true inactivation.

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Impact of Sorbic Acid on Germinant Receptor-Dependent and -Independent Germination Pathways inBacillus cereus

Applied and Environmental Microbiology ◽

10.1128/aem.02520-10 ◽

2011 ◽

Vol 77 (7) ◽

pp. 2552-2554 ◽

Cited By ~ 13

Author(s):

C. C. J. van Melis ◽

M. N. Nierop Groot ◽

T. Abee

Keyword(s):

Signal Transduction ◽

Amino Acid ◽

Hydrostatic Pressure ◽

Bacillus Cereus ◽

High Hydrostatic Pressure ◽

Sorbic Acid ◽

Dipicolinic Acid ◽

Acid Exposure

ABSTRACTAmino acid- and inosine-induced germination ofBacillus cereusATCC 14579 spores was reversibly inhibited in the presence of 3 mM undissociated sorbic acid. Exposure to high hydrostatic pressure, Ca-dipicolinic acid (DPA), and bryostatin, an activator of PrkC kinase, negated this inhibition, pointing to specific blockage of signal transduction in germinant receptor-mediated germination.

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Synergetic Inactivation Mechanism of Protocatechuic Acid and High Hydrostatic Pressure against Escherichia coli O157:H7

Foods ◽

10.3390/foods10123053 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3053

Author(s):

Jingyi Hao ◽

Yuqing Lei ◽

Zhilin Gan ◽

Wanbin Zhao ◽

Junyan Shi ◽

...

Keyword(s):

Escherichia Coli ◽

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Protocatechuic Acid ◽

Combined Treatment ◽

Membrane Integrity ◽

Escherichia Coli O157 ◽

Safety Issues ◽

Bactericidal Effects ◽

The Individual

With the wide application of high hydrostatic pressure (HHP) technology in the food industry, safety issues regarding food products, resulting in potential food safety hazards, have arisen. To address such problems, this study explored the synergetic bactericidal effects and mechanisms of protocatechuic acid (PCA) and HHP against Escherichia coli O157:H7. At greater than 200 MPa, PCA (1.25 mg/mL for 60 min) plus HHP treatments had significant synergetic bactericidal effects that positively correlated with pressure. After a combined treatment at 500 MPa for 5 min, an approximate 9.0 log CFU/mL colony decline occurred, whereas the individual HHP and PCA treatments caused 4.48 and 1.06 log CFU/mL colony decreases, respectively. Mechanistically, membrane integrity and morphology were damaged, and the permeability increased when E. coli O157: H7 was exposed to the synergetic stress of PCA plus HHP. Inside cells, the synergetic treatment additionally targeted the activities of enzymes such as superoxide dismutase, catalase and ATPase, which were inhibited significantly (p ≤ 0.05) when exposed to high pressure. Moreover, an analysis of circular dichroism spectra indicated that the synergetic treatment caused a change in DNA structure, which was expressed as the redshift of the characteristic absorption peak. Thus, the synergetic treatment of PCA plus HHP may be used as a decontamination method owing to the good bactericidal effects on multiple targets.

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Effects of High Hydrostatic Pressure Combined with Vacuum-Freeze Drying on the Aroma-Active Compounds in Blended Pumpkin, Mango, and Jujube Juice

Foods ◽

10.3390/foods10123151 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3151

Author(s):

Lin Yuan ◽

Xujuan Liang ◽

Xin Pan ◽

Fei Lao ◽

Yong Shi ◽

...

Keyword(s):

Hydrostatic Pressure ◽

Thermal Processing ◽

High Hydrostatic Pressure ◽

Volatile Compound ◽

Freeze Drying ◽

Combined Treatment ◽

Flavor Quality ◽

Untreated Sample ◽

Combination Process ◽

Gas Chromatography Olfactometry

A combination process of completely non-thermal processing methods involving high hydrostatic pressure (HHP) and vacuum-freeze drying (VFD) for producing a new snack from fruit and vegetable blends was developed, and the effect of the process on flavor quality was investigated. The HHP–VFD treatment did not significantly reduce volatile compound contents compared to single HHP or VFD. Gas chromatography–olfactometry showed that HHP–VFD raised the contents of floral-like volatile compounds (e.g., β-ionone) compared to the untreated sample. Sensory evaluation analysis confirmed that the overall liking was unchanged after the HHP–VFD treatment. The HHP–VFD combined treatment is effective in maintaining the flavor and extending shelf life, and is convenient for the portability and transportation of ready-to-drink juice.

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