Changes in microbial populations on fresh cut spinach

A comparison of sanitizers for fresh-cut mango (Mangifera indica cv. Keitt) was made. Mangos were obtained from a farm in Homestead, Fla., and stored at 15 °C until processed. Before cutting, fruit were dipped in solutions of either sodium hypochlorite (NaOCl) (200 ppm) or peroxyacetic acid (100 ppm). The cut pieces were dipped in acidified sodium chlorite (NaClO2) (200 ppm, pH 2.6) or dilute peroxyacetic acid (50 ppm) for 30 seconds. Resulting cut slices were placed in polystyrene clamshell food containers and stored at 5 °C for 21 days. Samples in the clamshells were tested for changes in microbial stability and for quality parameters every 7 days. Results showed that even though the fruit slices were sanitized after cutting, cut fruit microbial populations were related to the method of whole fruit sanitation. After 15-21 days in storage at 5 °C, cut slices from whole fruit sanitized with peroxyacetic acid that were subsequently treated with dilute peroxyacetic acid or acidified NaClO2 had less contamination [<1 colony-forming unit (cfu) per gram] than samples cut from whole fruit sanitized with NaOCl (<1000 to 3700 cfu/g). These data demonstrate that the method of whole fruit sanitation plays a role in determining the cleanliness of the cut fruit. These sanitizer systems (peroxyacetic acid on whole fruit followed by peroxyacetic acid or acidified NaClO2 on cut slices) effectively reduced microbial growth and kept microbial counts low on cut fruit surfaces for 21 days when compared to cut fruit slices from NaOCl-treated whole fruit.

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VAPOR HEAT TREATMENT EFFECTS ON MICROBIAL POPULATIONS AND SENSORY QUALITY OF FRESH-CUT BROCCOLI FLORETS

Acta Horticulturae ◽

10.17660/actahortic.2013.989.23 ◽

2013 ◽

pp. 185-191

Author(s):

P. Renumarn ◽

V. Srilaong ◽

A. Uthairatanakij ◽

S. Kanlayanarat ◽

P. Jitareerat

Keyword(s):

Heat Treatment ◽

Sensory Quality ◽

Treatment Effects ◽

Microbial Populations ◽

Fresh Cut

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Effects of ozone on major antioxidants and microbial populations of fresh-cut papaya

Postharvest Biology and Technology ◽

10.1016/j.postharvbio.2013.11.006 ◽

2014 ◽

Vol 89 ◽

pp. 56-58 ◽

Cited By ~ 50

Author(s):

Wei Keat Yeoh ◽

Asgar Ali ◽

Charles F. Forney

Keyword(s):

Microbial Populations ◽

Fresh Cut

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Microbial populations of fresh-cut spinach leaves affected by controlled atmospheres

Postharvest Biology and Technology ◽

10.1016/s0925-5214(96)00047-6 ◽

1996 ◽

Vol 9 (2) ◽

pp. 187-193 ◽

Cited By ~ 62

Author(s):

Isabelle Babic ◽

A.E. Watada

Keyword(s):

Microbial Populations ◽

Controlled Atmospheres ◽

Fresh Cut ◽

Spinach Leaves

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Prediction of Microbial Growth in Fresh-Cut Vegetables Treated with Acidic Electrolyzed Water during Storage under Various Temperature Conditions

Journal of Food Protection ◽

10.4315/0362-028x-64.12.1935 ◽

2001 ◽

Vol 64 (12) ◽

pp. 1935-1942 ◽

Cited By ~ 63

Author(s):

SHIGENOBU KOSEKI ◽

KAZUHIKO ITOH

Keyword(s):

Recovery Time ◽

Microbial Growth ◽

Microbial Population ◽

Storage Temperature ◽

Coliform Bacteria ◽

Microbial Populations ◽

Electrolyzed Water ◽

C Storage ◽

Fresh Cut ◽

Kinetics Of

Effects of storage temperature (1, 5, and 10°C) on growth of microbial populations (total aerobic bacteria, coliform bacteria, Bacillus cereus, and psychrotrophic bacteria) on acidic electrolyzed water (AcEW)-treated fresh-cut lettuce and cabbage were determined. A modified Gompertz function was used to describe the kinetics of microbial growth. Growth data were analyzed using regression analysis to generate “best-fit” modified Gompertz equations, which were subsequently used to calculate lag time, exponential growth rate, and generation time. The data indicated that the growth kinetics of each bacterium were dependent on storage temperature, except at 1°C storage. At 1°C storage, no increases were observed in bacterial populations. Treatment of vegetables with AcEW produced a decrease in initial microbial populations. However, subsequent growth rates were higher than on nontreated vegetables. The recovery time required by the reduced microbial population to reach the initial (treated with tap water [TW]) population was also determined in this study, with the recovery time of the microbial population at 10°C being <3 days. The benefits of reducing the initial microbial populations on fresh-cut vegetables were greatly affected by storage temperature. Results from this study could be used to predict microbial quality of fresh-cut lettuce and cabbage throughout their distribution.

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ATP Bioluminescence Assay for Estimation of Microbial Populations of Fresh-Cut Melon†

Journal of Food Protection ◽

10.4315/0362-028x-68.11.2427 ◽

2005 ◽

Vol 68 (11) ◽

pp. 2427-2432 ◽

Cited By ~ 19

Author(s):

DIKE O. UKUKU ◽

GERALD M. SAPERS ◽

WILLIAM F. FETT

Keyword(s):

Firefly Luciferase ◽

Luciferase Assay ◽

Microbial Populations ◽

Plate Count ◽

Initial Population ◽

Bacterial Counts ◽

Mesophilic Bacteria ◽

Atp Assay ◽

Plate Count Agar ◽

Fresh Cut

Estimation of microbial numbers in foods by conventional microbiological techniques takes days, so there is a need for faster methods that can give results in minutes. Research was undertaken to investigate the use of bioluminescent ATP determination and a firefly luciferase assay to estimate the initial population of aerobic mesophilic bacteria on fresh-cut melons immediately after preparation and during storage at 5 or 15°C for up to 12 days. Populations of aerobic mesophilic bacteria on fresh-cut cantaloupe prepared immediately from unsanitized whole melons averaged 3.42 log CFU/g, corresponding to an ATP value of 5.40 log fg/g. Populations for fresh-cut honeydew prepared from unsanitized whole melon averaged 1.97 log CFU/g, corresponding an ATP value of 3.94 log fg/g. Fresh-cut pieces prepared from cantaloupe or honeydew melons sanitized with either chlorine (200 ppm free chlorine) or hydrogen peroxide (2.5%) had similar ATP values: 3.1 log fg/g (corresponding to bacterial counts 1.7 log CFU/g) for cantaloupes and 2.6 log fg/g (corresponding to bacterial counts of 0.48 CFU/g) for fresh-cut honeydew. Positive linear correlations for ATP concentrations and microbial populations were found for fresh-cut cantaloupe (R2 = 0.99) and honeydew R2 = 0.95) during storage at 5°C for up to 12 days. ATP values in fresh-cut melons inoculated with either aerobic mesophilic bacteria or yeast and mold were significantly higher (P < 0.05) than control values and parallel total plate counts on plate count agar. Results of this study indicate that the bioluminescent ATP assay can be used to monitor total microbial populations on fresh-cut melon after preparation and during storage for quality control purposes to establish specific sell-by or consume-by dates.

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Improving the Microbiological Quality and Safety of Fresh-Cut Tomatoes by Low-Dose Electron Beam Irradiation

Journal of Food Protection ◽

10.4315/0362-028x-69.3.575 ◽

2006 ◽

Vol 69 (3) ◽

pp. 575-581 ◽

Cited By ~ 35

Author(s):

HEATHER MARTIN SCHMIDT ◽

MANGESH P. PALEKAR ◽

JOSEPH E. MAXIM ◽

ALEJANDRO CASTILLO

Keyword(s):

Electron Beam ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Electron Beam Irradiation ◽

Microbiological Quality ◽

Microbial Populations ◽

Quality And Safety ◽

Beam Irradiation ◽

Irradiation Treatment ◽

Fresh Cut

The effect of electron beam irradiation on microbiological quality and safety of fresh-cut tomatoes was studied. Fresh tomatoes were obtained from a local supplier and then cut into cubes that were separated from the stem scars. Both cubes and stem scars were inoculated with a rifampin-resistant strain of either Salmonella Montevideo or Salmonella Agona, separated into treatment groups, and treated by electron beam irradiation at 0.0 (control), 0.7, or 0.95 kGy. The effect of electron beam irradiation on Salmonella, lactic acid bacteria, yeast, and mold counts and pH of tomato cubes and stem scars was determined over a 15-day storage period at 4°C. Results indicated that although irradiation treatment significantly reduced most microbial populations on tomato samples, there were no differences in the reduction of microbial populations between treatments of 0.7 and 0.95 kGy. Irradiation at either dose resulted in a significant reduction in Salmonella when compared with the control (P < 0.05). Lactic acid bacteria, yeasts, and molds were more resistant to irradiation than were Salmonella. No differences were detected between the two Salmonella serotypes in response to irradiation treatment. These results indicate that irradiation at doses of at least 0.7 kGy can be used for pathogen reduction in fresh-cut tomatoes. If the use of doses greater than 1 kGy were approved, this technology might be very effective for use in fresh-cut tomatoes to eliminate significant populations of pathogens and to ensure the microbial quality of the product.

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