Ultra-High Pressure Pasteurization of Fresh Cut Pineapple

Ultra-high pressure (200, 270 and 340 MPa), temperature (~4, 21 and 38°C), and time (5, 15, 40 and 60 min) combinations were evaluated as a means to extend the shelf-life of fresh cut pineapple chunks. Cut pineapple obtained from an industrial processor was packed in heat-sealed polyethylene pouches. Triplicate samples were temperature adjusted and treated in an Autoclave Engineers IP2-22-60 isostatic press. Surviving bacteria and total yeast and mold counts were determined using plate count agar (PCA) and acidified potato dextrose agar (PDA), respectively. At the highest pressure (340 MPa) and 15 min, decimal reductions measured by growth on PCA were 3.0 (~4°C), 3.1 (21°C) and >2.5 (38°C). Pressure treated pineapple pieces had PCA counts < 50 colony forming units (CFU)/g. At 270 MPa and 15 min, greater than two decimal reductions were observed only at 38°C. Exposure to pressures of 200 MPa resulted in about one decimal reduction in PCA counts for all temperature and time combinations tested. PDA counts followed a similar behavior for all pressure treatments.

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Microbiological stabilization of tiger nuts’ milk beverage using ultra-high pressure homogenization. A preliminary study on microbial shelf-life extension

Food Microbiology ◽

10.1016/j.fm.2017.08.002 ◽

2018 ◽

Vol 69 ◽

pp. 143-150 ◽

Cited By ~ 19

Author(s):

I. Codina-Torrella ◽

B. Guamis ◽

A. Zamora ◽

J.M. Quevedo ◽

A.J. Trujillo

Keyword(s):

High Pressure ◽

Shelf Life ◽

Life Extension ◽

High Pressure Homogenization ◽

Ultra High Pressure ◽

Shelf Life Extension ◽

Preliminary Study ◽

Tiger Nuts

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Concurrent Effects of High Hydrostatic Pressure, Acidity and Heat on the Destruction and Injury of Yeasts

Journal of Food Protection ◽

10.4315/0362-028x-58.3.301 ◽

1995 ◽

Vol 58 (3) ◽

pp. 301-304 ◽

Cited By ~ 31

Author(s):

YOGA PANDYA ◽

FRED F. JEWETT ◽

DALLAS G. HOOVER

Keyword(s):

Saccharomyces Cerevisiae ◽

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Potato Dextrose Agar ◽

Plate Count ◽

Citrate Buffer ◽

Zygosaccharomyces Bailii ◽

Mild Heat ◽

Yeast Cultures ◽

Colony Forming Units

Saccharomyces cerevisiae ATCC 2373 and Zygosaccharomyces bailii ATCC 36947 were exposed to hydrostatic pressures ranging from 1,500 to 3,000 atmospheres for 10, 20 and 30 min in 0.1 M citrate buffer at pH 3.0, 4.0 and 5.0 at 25 and 45°C. Inactivation of inoculated yeast cultures was achieved in spaghetti sauce with meat at 25°C with 3,000 atmospheres for 10 min and also at 45°C and 2,500 atmospheres for 10 min. Viable counts were determined on potato dextrose agar (PDA) incubated at 30°C for 48 h. Pressure-induced injury was demonstrated by plate count differential between PDA and PDA supplemented with glucose (PDAG). A reduction of 7-log10 cycles colony forming units (CFU)/ml was seen for both strains at 3,000 atmospheres for 10 min at 25°C at all pH levels and at 2,250 atmospheres, pH 5.0 for 20 min at 45°C. At 2,000 atmospheres, pH 3.0 for 30 min, the increase in temperature from 25 to 45°C increased the inactivation of yeast by 6-log10 cycles. Lowering the pH from 5.0 to 3.0 enhanced lethality up to 2-log10 cycles at 2,250 atmospheres, 25°C for 30 min. Injury was most apparent at exposure parameters that produced 3- to 5-log10 cycle reductions on PDA. This was achieved (99% injury) at 2,250 atmospheres, 25°C for 30 min. These data indicate that mild heat and acidity contribute to the effectiveness of the inactivation and injury of yeast by high hydrostatic pressure (HHP).

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Shelf Life Extension of Maple pea (Pisum sativum var. arvense L.) Spread Using Sous Vide

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.1515/prolas-2016-0056 ◽

2016 ◽

Vol 70 (6) ◽

pp. 393-399

Author(s):

Asnate Ķirse ◽

Daina Kārkliņa ◽

Sandra Muižniece-Brasava

Keyword(s):

Pisum Sativum ◽

Shelf Life ◽

Life Extension ◽

Plate Count ◽

Plate Count Agar ◽

Total Plate Count ◽

Glucose Agar ◽

Sous Vide ◽

Cooking Times ◽

Ice Water

Abstract The aim of this study was to determine the effect of sous vide packaging on the shelf life of maple pea (Pisum sativum var. arvense L.) spread. Pea spreads were made of ground re-hydrated cooked maple peas ‘Bruno’ (Pisum sativum var. arvense L.), to which salt, citric acid, oil, and spices were added. Pea spread was stored in polyamide/polyethylene (PA/PE) film pouches, packaged in vacuum and hermetically sealed. Pea spread pouches were heat treated in a water bath, then rapidly cooled in ice-water and stored at 4.0 ± 0.5 °C. Sous vide was applied in three different heat regimens +(65.0; 80.0 and 100.0) ± 0.5 °C with cooking times 5, 10, 15, 20, 25, and 30 min at a constant temperature. Total plate count was determined according to ISO 4833-1:2014 on Plate Count Agar and Enterobacteriaceae determination was performed in accordance with ISO 21528-2:2004 on Violet Red Bile Glucose Agar. Total plate count in pea spread without thermal treatment was 3.41 log10 CFU g−1, in all sous vide packaged pea spread samples microbial contamination was significantly lower (p < 0.05). Enterobacteriaceae were not detected in any samples. It is possible to extend the shelf life of sous vide maple pea spread up to 14 weeks when stored at 4.0 ± 0.5 °C.

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Microbial contamination in dental unit waterlines

Brazilian Dental Journal ◽

10.1590/s0103-64402003000100010 ◽

2003 ◽

Vol 14 (1) ◽

pp. 55-57 ◽

Cited By ~ 15

Author(s):

Maria Cristina Monteiro de Souza-Gugelmin ◽

Carolina Della Torre Lima ◽

Sergio Narciso Marques de Lima ◽

Henis Mian ◽

Izabel Yoko Ito

Keyword(s):

High Speed ◽

Microbial Contamination ◽

Water Reservoir ◽

Plate Count ◽

Plate Count Agar ◽

Quality Of Water ◽

Colony Forming Units ◽

Dental Staff ◽

Dental Unit Waterlines

The quality of water in a dental unit is of considerable importance because patients and dental staff are regularly exposed to water and aerosol generated from the dental unit. The aim of this study was to evaluate the occurrence of microbial contamination in dental unit waterlines. Water samples were collected aseptically from the waterlines (reservoir, triple-syringe, high-speed) of 15 dental units. After serial dilution to 1:10(6) in APHA, the samples were seeded by the pour-plate technique and cultured in plate count agar (Difco) for 48 h at 32ºC. Analysis was based on the number of colony forming units (CFU). The Wilcoxon non-parametric test indicated that the levels of water contamination were highest in the triple-syringe (13 of 15) and in the high-speed (11 of 15); both levels were higher than those of the water reservoir. There was no significant statistical difference between the level of contamination in the triple-syringe and the high-speed as determined by the Mann-Whitney test [p(H0) = 40.98%; Z = - 0.2281]. Because biofilm forms on solid surfaces constantly bathed by liquid where microorganisms are present, these results indicate that the water in the dental unit may be contaminated by biofilm that forms in these tubules.

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Evaluation of a Culture Film (Petrifilm™ YM) Method for Enumerating Yeasts and Molds in Selected Dairy and High-Acid Foods

Journal of Food Protection ◽

10.4315/0362-028x-53.10.869 ◽

1990 ◽

Vol 53 (10) ◽

pp. 869-874 ◽

Cited By ~ 17

Author(s):

L. R. BEUCHAT ◽

B. V. NAIL ◽

R. E. BRACKETT ◽

T. L. FOX

Keyword(s):

Correlation Coefficients ◽

Food Products ◽

Cottage Cheese ◽

Plate Count ◽

Fungal Cell ◽

High Acid ◽

Plate Count Agar ◽

Sour Cream ◽

Yeasts And Molds ◽

Total Yeast

The Petrifilm™ Yeast and Mold (YM) plate was compared to acidified potato dextrose agar (APDA) and chloramphenicol-supplemented plate count agar (CPCA) using pour- and surface-plating techniques for its ability to recover yeasts and molds from hard and soft cheeses, cottage cheese, yogurt, sour cream, fruit juice, salad dressing, relishes, and tomato-based sauces. Correlation coefficients of Petrifilm™ YM plates versus pour-APDA, surface-APDA, pour-CPCA, and surface-CPCA for recovering total yeasts and molds from a composite of the eight test foods were, respectively, 0.993, 0.993, 0.994, and 0.995. Slope and intercept values for populations detected using Petrifilm™ YM plates versus traditional systems ranged, respectively, from 0.984 to 1.008 and −0.051 to 0.149. The coefficient of variation for total yeast and mold populations recovered on Petrifilm™ YM plates was 1.0% compared to 1.2 to 1.7% for traditional enumeration systems. Regardless of the enumeration system employed or the type of fungal cell, i.e., yeast or mold, being enumerated, significantly (P ≤ 0.05) higher populations were generally detected after 5 d compared to 3 d of incubation. After 5 d of incubation, in no case were yeast or total yeast and mold populations detected in the eight food products using Petrifilm™ YM plates significantly lower than respective populations detected using traditional pour- and surface-plating techniques and media. When Petrifilm™ YM plates were used, significantly higher total yeast and mold populations were detected in 3, 1, and 1 out of eight food products compared to using, respectively, pour-APDA, surface-APDA, and surface-CPCA enumeration systems. The Petrifilm™ YM plate offers an acceptable alternative to traditional methods for enumerating yeasts and molds in the dairy and high-acid products evaluated in this study.

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Reduction of Microbial Populations on Prunes by Vapor Phase Hydrogen Peroxide

HortScience ◽

10.21273/hortsci.30.4.815f ◽

1995 ◽

Vol 30 (4) ◽

pp. 815F-815

Author(s):

Gilbert F. Simmons ◽

Joseph L. Smilanick ◽

Shama John ◽

Dennis A. Margosan

Keyword(s):

Hydrogen Peroxide ◽

Vapor Phase ◽

Culture Medium ◽

Culture Media ◽

Microbial Populations ◽

Plate Count ◽

Potassium Sorbate ◽

Plate Count Agar ◽

Colony Forming Units ◽

Aerobic Plate Count

Moisture is raised in dehydrated prunes to improve palatability before packaging and potassium sorbate is added to inhibit microbial growth. Vapor phase hydrogen peroxide (VPHP) technology uses hydrogen peroxide pulses to disinfect dried prunes. Dried prunes were obtained from dehydrators. The number of colony-forming units per 10 prunes (cfu/p) was compared between untreated and VPHP treated. Three culture media—dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (PCA), and potato dextrose agar (PDA)—were used to evaluate cfu/p. Similar mean microbe populations were observed on DRBC (67) and PDA (70); PCA had higher cfu/p (99). Microbes washed from untreated prunes obtained from dehydrators were 58 to 112 cfu/p, depending on the culture medium used. The number of cfu/p assessed on all media on VPHP-treated prunes was near 0 after 100 min exposure. Unlike potassium sorbate, hydrogen peroxide is a microbiocide rather than a microbiostat.

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Effect of High-Pressure Processing on Microbial Quality of Skimmed Milk

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.2478/prolas-2018-0019 ◽

2018 ◽

Vol 72 (2) ◽

pp. 118-122

Author(s):

Marika Liepa ◽

Jelena Zagorska ◽

Ruta Galoburda ◽

Svetlana Kostascuka

Keyword(s):

High Pressure ◽

Microbiological Quality ◽

High Pressure Processing ◽

Biologically Active ◽

Life Extension ◽

Plate Count ◽

Colony Forming Units ◽

Skimmed Milk ◽

Active Substances

Abstract High pressure processing (HPP) is an alternative to traditional thermal treatment and can be used in the dairy industry for increasing the microbiological safety of milk and for preserving its biologically active substances. HPP effectiveness in providing microbiological quality of product is still under discussion; thus, the aim of the study was to evaluate the effect of HPP technology on microbiological quality of skimmed milk. Raw, pasteurised (78 °C, 15–20 s), HPP treated (250 MPa, 15 min; 400 MPa, 3 min; 400 MPa, 15 min; 550 MPa, 3 min) and skimmed milk, processed by combining pasteurisation and HPP were analysed and compared. The total plate count (LVS ISO 4833-1:2013) and presence of coliforms (LVS EN ISO 16654:2002) were determined in analysed skimmed milk samples. Significant decrease (p < 0.05) of colony forming units (CFU) was observed in samples processed by combining two treatment types: pasteurisation and HPP. The minimum treatment parameters for shelf-life extension of skimmed milk were determined: pressure not less than 400 MPa and holding time at least 15 minutes.

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