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

2018 ◽  
Vol 24 (6) ◽  
pp. 1021-1027
Author(s):  
Xiaoting Yin ◽  
Yincheng Zhang ◽  
Sicong Tu ◽  
Yangmin Huang ◽  
Kang Tu
1999 ◽  
Vol 62 (10) ◽  
pp. 1128-1135 ◽  
Author(s):  
L. JACXSENS ◽  
F. DEVLIEGHERE ◽  
P. FALCATO ◽  
J. DEBEVERE

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.


Author(s):  
Md. Azizul Haque ◽  
Md. Asaduzzaman ◽  
Md. Sultan Mahomud ◽  
Md. Rizvi Alam ◽  
Alin Khaliduzzaman ◽  
...  

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.


2006 ◽  
Vol 69 (10) ◽  
pp. 2524-2528 ◽  
Author(s):  
GILLIAN A. FRANCIS ◽  
DAVID O'BEIRNE

The incidence of Listeria monocytogenes in modified atmosphere packaged fresh-cut fruits and vegetables from chill cabinets of a supermarket in Ireland was investigated over a 2-year period. Overall, 9.58% of fresh-cut produce was contaminated with Listeria spp. Various species of Listeria were isolated from samples, including L. monocytogenes, L. seeligeri, L. innocua, L. welshimeri, and L. ivanovii. No fruit samples contained detectable L. monocytogenes. Overall, a total of 21 L. monocytogenes isolates (2.9% of samples) were recovered from a range of products, including dry coleslaw mix (80% shredded cabbage and 20% shredded carrot), bean sprouts, and leafy vegetables such iceberg, romaine, and radicchio lettuce and mixed salad leaves (curly endive, escarole, and radicchio leaves). Dry coleslaw mix appeared to have the highest incidence of Listeria contamination (20%) compared with other products. Listeria contamination was more frequent (P < 0.05) during the summer and autumn months than during the winter and spring months. The 21 L. monocytogenes isolates were subsequently subtyped by genomic macrorestriction techniques using ApaI with pulsed-field gel electrophoresis (PFGE). PFGE of digested DNA produced bands of 79 to 518 kb. Four PFGE profiles were identified, and approximately 50% of the isolates were associated with profile 1. This study indicates that fresh-cut vegetables packaged under a modified atmosphere can support growth of numerous species of Listeria, including L. monocytogenes.


Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1211
Author(s):  
Paul Culliney ◽  
Achim Schmalenberger

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.


Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 988
Author(s):  
Bernardo Pace ◽  
Imperatrice Capotorto ◽  
Michela Palumbo ◽  
Sergio Pelosi ◽  
Maria Cefola

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.


2019 ◽  
Vol 82 (2) ◽  
pp. 287-300 ◽  
Author(s):  
VICTOR JAYEOLA ◽  
SANGHYUP JEONG ◽  
EVA ALMENAR ◽  
BRADLEY P. MARKS ◽  
KEITH L. VORST ◽  
...  

ABSTRACT Temperature is arguably the most important factor affecting microbial proliferation in fresh-cut produce. In this study, growth of Listeria monocytogenes in diced onions and celery and Salmonella Typhimurium in diced tomatoes was determined in modified atmosphere packages and snap-fit containers using three fluctuating temperature scenarios for transport, retail storage, and display. As expected, L. monocytogenes growth in diced onions and celery varied depending on the extent of temperature abuse, with exposure to high and intermediate temperature-abuse scenarios generally being growth supportive. A Baranyi primary model with a square-root secondary model for maximum growth rate, and a linear model for maximum population density, were used to estimate Listeria growth under fluctuating temperature. Accuracy and acceptability of the model prediction were evaluated in terms of root mean square error (RMSE) and acceptable prediction zone (APZ), respectively. Overall, growth predictions for L. monocytogenes were more accurate for celery (RMSE, 0.28 to 0.47) than onions (RMSE, 0.42 to 1.53) under the fluctuating temperature scenarios tested. However, both predictions yielded APZ values that ranged from 82 to 100% for celery and 36 to 78% for onions. In contrast, Salmonella Typhimurium populations increased more than 1 log CFU/g in diced tomatoes under the three fluctuating temperature scenarios studied. Overall, these diced products packaged under a high-oxygen atmosphere showed decreased pathogen growth compared with product stored in a passive modified atmosphere. Findings from this study will be particularly useful in assessing the risk associated with consumption of diced celery, tomatoes, and onions and in designing effective packaging strategies to minimize pathogen growth in fresh-cut produce.


2017 ◽  
Vol 124 ◽  
pp. 91-99 ◽  
Author(s):  
M.J.M. Paillart ◽  
J.M.B.M. van der Vossen ◽  
E. Levin ◽  
E. Lommen ◽  
E.C. Otma ◽  
...  

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 273-277 ◽  
Author(s):  
Xuetong Fan ◽  
Kimberly J.B. Sokorai

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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