Nisin application delays growth of Listeria monocytogenes on fresh-cut iceberg lettuce in modified atmosphere packaging, while the bacterial community structure changes within one week of storage

AbstractFresh-cut lettuce is a very well-known salad for today's routines because it obliges minimal preparation to minimize the loss of health beneficial vitamins, minerals, antioxidants and other phytochemicals. It is a prodigious challenge to serve its consumers fresh. Quality of freshly processed lettuce under high CO2 modified atmosphere packaging (MAP) has been investigated as a realistic alternative technique for its preservation. Storage under high CO2 atmospheric treatments exhibited a significant impact in microbial development, electrolyte leakage, volatile metabolites and sensory quality of fresh-cut iceberg lettuce. This storage condition (MAP 1: 5 kPa O2 and 20 kPa CO2 balanced by N2 at 7 °C for 6 days) inhibited the growth of mesophilic bacteria and yeasts; delayed the enzymatic browning (cut-edges and intact surface) of fresh-cut iceberg lettuce and overall visual quality was also in acceptance limit. The development of off-odors was perceived in high CO2 MAP as a consequence of volatiles (ethanol and acetaldehyde) accumulation which was persisted at an inexcusable level during 6 days of storage periods.

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Growth Potential of Listeria monocytogenes on Refrigerated Spinach and Rocket Leaves in Modified Atmosphere Packaging

Foods ◽

10.3390/foods9091211 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1211

Author(s):

Paul Culliney ◽

Achim Schmalenberger

Keyword(s):

Listeria Monocytogenes ◽

Modified Atmosphere Packaging ◽

Growth Curves ◽

High Growth ◽

Food Product ◽

Growth Potential ◽

Modified Atmosphere ◽

Visual Appearance ◽

Iceberg Lettuce ◽

Duration Of Storage

Minimally processed ready-to-eat (RTE) vegetables are increasingly consumed for their health benefits. However, they also pose a risk of being ingested with food-borne pathogens. The present study investigated the ability of RTE spinach and rocket to support the growth of Listeria monocytogenes as previous studies provided contradicting evidence. Findings were compared to growth on iceberg lettuce that has repeatedly been shown to support growth. Products were inoculated with a three-strain mix of L. monocytogenes at 10 and 100 cfu g−1 and stored in modified atmosphere (4 kPa O2, 8 kPa CO2) at 8 °C over 7–9 days. Spinach demonstrated the highest growth potential rate of 2 to 3 log10 cfu g−1 over a 9-day period with only marginal deterioration in its visual appearance. Growth potential on rocket was around 2 log10 cfu g−1 over 9 days with considerable deterioration in visual appearance. Growth potential of iceberg lettuce was similar to that of rocket over a 7-day period. Growth curves fitted closely to a linear growth model, indicating none to limited restrictions of growth over the duration of storage. The high growth potentials of L. monocytogenes on spinach alongside the limited visual deterioration highlight the potential risks of consuming this raw RTE food product when contaminated.

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Combined Effect of Dipping in Oxalic or in Citric Acid and Low O2 Modified Atmosphere, to Preserve the Quality of Fresh-Cut Lettuce during Storage

Foods ◽

10.3390/foods9080988 ◽

2020 ◽

Vol 9 (8) ◽

pp. 988

Author(s):

Bernardo Pace ◽

Imperatrice Capotorto ◽

Michela Palumbo ◽

Sergio Pelosi ◽

Maria Cefola

Keyword(s):

Citric Acid ◽

Respiration Rate ◽

Modified Atmosphere Packaging ◽

Packaging Material ◽

Combined Effect ◽

Modified Atmosphere ◽

Iceberg Lettuce ◽

Fresh Cut ◽

Main Factor

Leaf edge browning is the main factor affecting fresh-cut lettuce marketability. Dipping in organic acids as well as the low O2 modified atmosphere packaging (MAP), can be used as anti-browning technologies. In the present research paper, the proper oxalic acid (OA) concentration, able to reduce respiration rate of fresh-cut iceberg lettuce, and the suitable packaging materials aimed to maintaining a low O2 during storage, were selected. Moreover, the combined effect of dipping (in OA or in citric acid) and packaging in low O2 was investigated during the storage of fresh-cut iceberg lettuce for 14 days. Results showed a significant effect of 5 mM OA on respiration rate delay. In addition, polypropylene/polyamide (PP/PA) was select as the most suitable packaging material to be used in low O2 MAP. Combining OA dipping with low O2 MAP using PP/PA as material, resulted able to reduce leaf edge browning, respiration rate, weight loss and electrolyte leakage, preserving the visual quality of fresh-cut lettuce until 8 days at 8 °C.

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SOIL BACTERIAL COMMUNITY STRUCTURE CHANGES FOLLOWING DISTURBANCE OF THE OVERLYING PLANT COMMUNITY

Soil Science ◽

10.1097/01.ss.0000112014.97541.ba ◽

2004 ◽

Vol 169 (1) ◽

pp. 55-65 ◽

Cited By ~ 23

Author(s):

Sanghoon Kang ◽

Aaron L. Mills

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Plant Community ◽

Bacterial Community Structure ◽

Soil Bacterial Community ◽

Structure Changes ◽

Soil Bacterial Community Structure ◽

Soil Bacterial

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Effects of Gamma Irradiation, Modified Atmosphere Packaging, and Delay of Irradiation on Quality of Fresh-cut Iceberg Lettuce

HortScience ◽

10.21273/hortsci.46.2.273 ◽

2011 ◽

Vol 46 (2) ◽

pp. 273-277 ◽

Cited By ~ 9

Author(s):

Xuetong Fan ◽

Kimberly J.B. Sokorai

Keyword(s):

Gamma Irradiation ◽

Modified Atmosphere Packaging ◽

Visual Quality ◽

Modified Atmosphere ◽

Cut Edge ◽

Quality Deterioration ◽

Iceberg Lettuce ◽

Fresh Cut ◽

Tissue Browning

This study was conducted to investigate the effect of modified atmosphere packaging (MAP) and delay of irradiation application on the quality of cut Iceberg lettuce. Overall visual quality and tissue browning of cut lettuce were evaluated using a scale of 9 to 1, whereas texture was analyzed instrumentally during 14 days of storage at 4 °C. Results showed that irradiation (0.5 and 1.0 kGy) of cut lettuce induced tissue browning when stored in air; however, when cut lettuce was stored in MAP, irradiated lettuce had better appearance than the non-irradiated ones as a result of lower O2 levels in the packages of irradiated samples compared with the levels in control packages. In general, irradiation at doses of 0.5 and 1.0 kGy did not affect firmness of the lettuce. After 14 days of MAP storage, overall visual quality of non-irradiated samples had a score of ≈4, a score below the limit of sales appeal, whereas the two irradiated samples had scores of 6.5 to 7.9, indicating the irradiated samples had a fair to good quality. Delaying irradiation by 1 day after preparation of cut lettuce did not significantly (P > 0.05) affect cut edge browning, surface browning, or overall visual quality compared with lettuce irradiated immediately after preparation. Our results suggest that MAP is essential to minimize quality deterioration caused by irradiation.

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Model for the Effect of Carbon Dioxide on Listeria Monocytogenes in Fresh-cut Iceberg Lettuce Packaged Under Modified Atmosphere

Food Science and Technology Research ◽

10.3136/fstr.24.1021 ◽

2018 ◽

Vol 24 (6) ◽

pp. 1021-1027

Author(s):

Xiaoting Yin ◽

Yincheng Zhang ◽

Sicong Tu ◽

Yangmin Huang ◽

Kang Tu

Keyword(s):

Carbon Dioxide ◽

Listeria Monocytogenes ◽

Modified Atmosphere ◽

Iceberg Lettuce ◽

Fresh Cut

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Behavior of Listeria monocytogenes and Aeromonas spp. on Fresh-Cut Produce Packaged under Equilibrium-Modified Atmosphere

Journal of Food Protection ◽

10.4315/0362-028x-62.10.1128 ◽

1999 ◽

Vol 62 (10) ◽

pp. 1128-1135 ◽

Cited By ~ 99

Author(s):

L. JACXSENS ◽

F. DEVLIEGHERE ◽

P. FALCATO ◽

J. DEBEVERE

Keyword(s):

Listeria Monocytogenes ◽

Shelf Life ◽

Microbiological Quality ◽

Modified Atmosphere ◽

Brussels Sprouts ◽

Iceberg Lettuce ◽

Aeromonas Caviae ◽

Taste And Odor ◽

Microbiological Criteria ◽

Fresh Cut

Storage experiments were conducted to follow the behavior of pathogens on fresh-cut vegetables (trimmed brussels sprouts, grated carrots, shredded iceberg lettuce, and shredded chicory endives) packaged under an equilibrium-modified atmosphere (EMA) (2 to 3% O2, 2 to 3% CO2, and 94 to 96% N2) and stored at 7°C. As a comparison, fresh-cut vegetables were also packaged in a perforated high-barrier film (air conditions) and stored at 7°C. In a first step, the shelf life of the vegetables in the two kinds of packages was determined by evaluating the microbiological quality as well as the sensorial quality (appearance, taste, and odor). In general, sensorial properties were faster in limiting the shelf life than microbiological criteria. The shelf life of the vegetables stored under an EMA was extended by 50% or more, compared with the air-stored vegetables. In a second storage experiment, the four fresh-cut vegetables were inoculated with a cocktail of psychrotrophic pathogens (Listeria monocytogenes, Aeromonas caviae [HG4]) and A. bestiarum (HG2) before packaging under an EMA and air at 7°C. The inoculated pathogens were more influenced by the type of vegetable than by the type of atmosphere. No growth was detected on the brussels sprouts or on carrots (L. monocytogenes). Aeromonas spp. had a higher growth rate than L. monocytogenes on the shredded chicory endives and shredded iceberg lettuce at 7°C.

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Study on degradation characteristics and bacterial community structure changes of immobilized cells in straw-alginate beads in marine environment

Bioresource Technology Reports ◽

10.1016/j.biteb.2020.100402 ◽

2020 ◽

Vol 10 ◽

pp. 100402 ◽

Cited By ~ 1

Author(s):

Jianliang Xue ◽

Yanan Wu ◽

Xinge Fu ◽

Nana Li ◽

Jingkuan Sun ◽

...

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Marine Environment ◽

Bacterial Community Structure ◽

Immobilized Cells ◽

Alginate Beads ◽

Structure Changes

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Pastureland intensification and diversification in Brazil mediate soil bacterial community structure changes and soil C accumulation

Applied Soil Ecology ◽

10.1016/j.apsoil.2020.103858 ◽

2021 ◽

Vol 160 ◽

pp. 103858

Author(s):

Júnior Melo Damian ◽

Eduardo da Silva Matos ◽

Bruno Carneiro e Pedreira ◽

Paulo César de Faccio Carvalho ◽

Adijailton José de Souza ◽

...

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Bacterial Community Structure ◽

Soil Bacterial Community ◽

Soil C ◽

Structure Changes ◽

Soil Bacterial Community Structure ◽

Soil Bacterial

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Respiration rate and ethylene production of fresh cut lettuce as affected by cutting grade

Agricultural and Food Science ◽

10.2137/145960605775897669 ◽

2008 ◽

Vol 14 (4) ◽

pp. 354 ◽

Cited By ~ 10

Author(s):

J. MARTÍNEZ ◽

A. CHIESTA ◽

F. TOVAR

Keyword(s):

Respiration Rate ◽

Ethylene Production ◽

Modified Atmosphere Packaging ◽

Anaerobic Respiration ◽

Polymeric Films ◽

Modified Atmosphere ◽

Minimally Processed ◽

Iceberg Lettuce ◽

High O2 ◽

Fresh Cut

For designing optimal polymeric films for modified atmosphere packaging of whole heads as well as for minimally fresh processed (fresh-cut) Iceberg lettuce Coolguard, the effect of several cutting grades on respiration rate (RR) and ethylene production at 5ºC was studied. According to common industrial practices cutting grades less than 0.5 cm, between 0.5 and 1 cm, and 2 cm length were selected. Results from four experiments were compared to those obtained for whole heads in which a homogenous range of 6 to 8 ml CO2 kg-1 h-1 in RR was found. Compared to whole heads, in fresh-cut lettuce the RR was 2-fold higher. The lowest cutting grade showed the highest respiration rate, and no significant differences in RR among lettuce pieces of intermediate and the highest grades were found. No ethylene production was detected in whole heads, while in minimally processed lettuce pieces only traces were found. For avoiding risks of anaerobic respiration and excessive CO2 levels within packages containing fresh-cut lettuce pieces lower than 0.5 cm length, films with relatively high O2 permeability like standard polypropylene or low-density polyethylene must be selected.;

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