Growth of Listeria monocytogenes Inoculated on Packaged Fresh-Cut Turnips Stored at 4 and 10°C

2020 ◽  
Vol 83 (8) ◽  
pp. 1296-1301
Author(s):  
GRANT L. BRIERLEY ◽  
VALERIA R. PARREIRA ◽  
JEFFREY M. FARBER ◽  
FRANCO PAGOTTO
Keyword(s):  
Listeria Monocytogenes ◽  
Temperature Control ◽  
Initial Level ◽  
Storage Period ◽  
Growth Potential ◽  
Minimally Processed ◽  
Bacterial Microbiota ◽  
Fresh Cut

ABSTRACT The ecology of Listeria monocytogenes has been previously investigated in various whole and minimally processed raw vegetables, but not in turnips. A 2018 national Canadian recall for packaged fresh-cut turnips contaminated with L. monocytogenes raised concerns about turnips being able to support the growth of this microorganism. Thus, this study examined the growth potential of L. monocytogenes in fresh-cut turnips stored at 4 and 10°C. The bacterial microbiota of each brand of purchased turnips was also partially determined to evaluate the diversity of bacteria present on the product. Turnips were mist inoculated at an initial level of 3.0 log CFU/g using a five-strain L. monocytogenes cocktail. Samples were then stored at either 4 or 10°C for 10 days, with enumeration occurring at 0, 5, and 10 days. L. monocytogenes did grow on turnips stored at 10°C, with increases ranging from 0.87 to 1.84 log CFU/g over the 10-day storage period (P < 0.05). In contrast, L. monocytogenes was able to survive but not grow on turnips stored at 4°C for 10 days. This study reinforces the importance of strict temperature control within processing, retail, and household consumer settings. Avoiding temperature abuse conditions and storing packaged fresh-cut turnips under refrigerator conditions (≤4°C) can serve as an important hurdle to prevent and/or limit the growth of L. monocytogenes on these products. HIGHLIGHTS

scholarly journals Effects of several sanitisers for improving quality attributes of minimally processed Fragaria vesca strawberry

2013 ◽  
Vol 31 (No. 1) ◽  
pp. 49-54 ◽  
Author(s):  
S. Nogales-Delgado ◽  
A.M. Fernández-León ◽  
J. Delgado-Adámez ◽  
M.T. Hernández-Méndez ◽  
D. Bohoyo-Gil
Keyword(s):  
Lactic Acid ◽  
Sodium Hypochlorite ◽  
Storage Period ◽  
Good Alternative ◽  
Sensory Attributes ◽  
Minimally Processed ◽  
Microbial Counts ◽  
Fresh Cut ◽  
Washing Water

In order to decrease microbial contamination, fresh-cut industry commonly uses sodium hypochlorite as a disinfection agent, however, the by-products such as trihalometanes and chloramines are potentially harmful for human health making necessary the search for alternative disinfectant agents. A comparative study on the effectiveness of different disinfection methods on the quality of minimally processed F. vesca strawberry is presented. The fruit was processed in a clean room through the following steps: reception, cutting, washing, draining, and packaging. The processed strawberries were packaged in thermally sealed polypropylene trays using passive modified atmosphere. During a storage period of 8 days at 4ºC, the quality parameters, sensory attributes, and microbial counts were determined. As conclusion, the use of lactic acid at a concentration of 2.5 g/l in the washing water was effective in reducing microbial counts, maintaining the sensory attributes and quality of the product during the storage. The present study demonstrates that the use of lactic acid in the washing water could be a good alternative of the use of sodium hypochlorite and suggests that strawberries could make an acceptable fresh-cut product.  

Changes in Populations of Listeria monocytogenes Inoculated on Packaged Fresh-Cut Vegetables

1998 ◽  
Vol 61 (2) ◽  
pp. 192-195 ◽  
Author(s):  
J. M. FARBER ◽  
S. L. WANG ◽  
Y. CAI ◽  
S. ZHANG
Keyword(s):  
Listeria Monocytogenes ◽  
Extreme Temperature ◽  
Storage Period ◽  
Population Increase ◽  
Good Growth ◽  
Cell Numbers ◽  
Unit Increase ◽  
Fresh Cut ◽  
Subsequent Storage ◽  
Mix Temperature

A variety of Wholesale and retail packaged vegetables and salads were inoculated with a mixture of strains of Listeria monocytogenes and incubated at 4 and 10°C. Whole rutabagas, butternut squash, and onions, as well as packaged Caesar salad, carrots, coleslaw mix, and stir-fry vegetables were purchased from local supermarkets in the Ottawa area. L. monocytogenes population levels remained constant on all fresh-cut vegetables stored at 4°C for 9 days, except for carrots and butternut squash: counts of cell numbers declined on carrots and increased on the butternut squash. Fresh-cut vegetables stored at 10°C, however, supported good growth of L. monocytogenes on all vegetables tested, except for chopped carrots, where the population decreased approximately 2 log units over a 9-day storage period. As in the situation with the produce stored at 4°C, butternut squash supported the highest rate of cell growth. In addition, Caesar salad and coleslaw mix were kept at 25°C for 1 or 2 days before subsequent storage at 4 or 10°C to simulate extreme temperature-abuse conditions. In Caesar salad stored at 4°C, by day 6 an initial 24- and 48-h temperature abuse at 25°C led to a 1.21- and 2.55-log-unit population increase, respectively, over the control. Similar increases were observed on Caesar salads stored at 10°C. Compared to Caesar salad, coleslaw mix temperature-abused at 25°C and then stored at 4°C supported slightly greater increases in the population of L. monocytogenes, i.e., a 3.22- and 3.83-log-unit increase over the control for the 1- and 2-day abused samples, respectively. Coleslaw mix samples temperature-abused and then stored at 10°C, however, only showed log unit increases of 1.75 and 1.94, respectively, compared to the Controls. These results point to the importance of strict temperature control to prevent or reduce the growth of L. monocytogenes cells on fresh-cut vegetables.

Survival and Growth of Listeria monocytogenes and Enterohemorrhagic Escherichia coli O157:H7 in Minimally Processed Artichokes

2003 ◽  
Vol 66 (12) ◽  
pp. 2203-2209 ◽  
Author(s):  
SUSANA SANZ ◽  
MERCEDES GIMÉNEZ ◽  
CARMEN OLARTE
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Tap Water ◽  
Storage Period ◽  
Enterohemorrhagic Escherichia Coli ◽  
Fecal Coliforms ◽  
Escherichia Coli O157 ◽  
Natural Background ◽  
Minimally Processed ◽  
E Coli

The ability of Listeria monocytogenes and Escherichia coli O157:H7 inoculated by immersion (at 4.6 and 5.5 log CFU/g, respectively) to survive on artichokes during various stages of preparation was determined. Peeling, cutting, and disinfecting operations (immersion in 50 ppm of a free chlorine solution at 4°C for 5 min) reduced populations of L. monocytogenes and E. coli O157:H7 by only 1.6 and 0.8 log units, respectively. An organic acid rinse (0.02% citric acid and 0.2% ascorbic acid) was more effective than a tap water rinse in removing these pathogens. Given the possibility of both pathogens being present on artichokes at the packaging stage, their behavior during the storage of minimally processed artichokes was investigated. For this purpose, batches of artichokes inoculated with L. monocytogenes or E. coli O157:H7 (at 5.5 and 5.2 log CFU/g, respectively) were packaged in P-Plus film bags and stored at 4°C for 16 days. During this period, the equilibrium atmosphere composition and natural background microflora (mesophiles, psychrotrophs, anaerobes, and fecal coliforms) were also analyzed. For the two studied pathogens, the inoculum did not have any effect on the final atmospheric composition (10% O2, 13% CO2) or on the survival of the natural background microflora of the artichokes. L. monocytogenes was able to survive during the entire storage period in the inoculated batches, while the E. coli O157:H7 level increased by 1.5 log units in the inoculated batch during the storage period. The modified atmosphere was unable to control the behavior of either pathogen.

scholarly journals Effect of carrot puree edible films on quality preservation of fresh-cut carrots

2015 ◽  
Vol 54 (1) ◽  
pp. 64-71 ◽  
Author(s):  
X. Wang ◽  
D. Kong ◽  
Z. Ma ◽  
R. Zhao
Keyword(s):  
Sensory Quality ◽  
Corn Starch ◽  
Storage Period ◽  
Edible Films ◽  
Significant Inhibition ◽  
Physiological Effects ◽  
Minimally Processed ◽  
Total Carotenoids ◽  
Fresh Cut ◽  
Carrot Puree

Abstract The effect of edible films based on carrot puree, chitosan, corn starch, gelatin, glycerol and cinnamaldehyde on fresh-cut carrots was studied during storage. Several parameters, such as firmness, colour, weight loss, total carotenoids, total phenols, polyphenol oxidase (PPO) activity and peroxidase (POD) activity in coated carrots were determined at regular intervals and then compared with the uncoated carrots throughout the storage period. Significant and expected changes were observed in all carrot samples that were compared. The coating treatment significantly (P < 0.05) delayed the senescence, reduced the deterioration of exterior quality and retained total carotenoids well compared with control (P < 0.05). In addition, significant inhibition of PPO activity (P < 0.05) and POD activity (P < 0.05) as well as reduced accumulation of polyphenols (P < 0.05) were observed for all coated samples. All of these favourable responses induced by coating treatment on minimally processed fresh-cut carrots showed beneficial physiological effects, which would give some useful references to the fresh-cut fruit and vegetable processing industry and satisfy people’s requirements allowing for extending product shelf life without negatively affecting the sensory quality or acceptability.

scholarly journals Growth potential of Listeria monocytogenes in six different RTE fruit products: impact of food matrix, storage temperature and shelf life

2018 ◽  
Vol 7 (3) ◽  
Author(s):  
Matthias Ziegler ◽  
Simon Rüegg ◽  
Roger Stephan ◽  
Claudia Guldimann
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Storage Temperature ◽  
Growth Potential ◽  
Food Matrix ◽  
Significant Growth ◽  
C Storage ◽  
Fresh Cut ◽  
And Storage ◽  
Storage Temperatures

We tested the growth potential of Listeria monocytogenes on six RTE fruit products at low (4°C at the factory followed by 8°C retail/home storage) and abusive (4°C followed by 12°C) storage temperatures. Sliced coconut and fresh cut cantaloupe, as well as a fruit mix containing diced pineapple, cantaloupe, apples and grapes supported the growth of L. monocytogenes with a growth potential d>0.5 log CFU/g over six days. Mangoes, a mix of diced kiwi, cantaloupe and pineapple as well as a mix of diced pineapple, mango, grapefruit, kiwi and pomegranate did not support a growth potential that exceeded 0.5 log CFU/g over six days. The growth potential of L. monocytogenes correlated significantly with the pH; no product with a pH below 4 showed a significant growth potential of L. monocytogenes. Time after inoculation was also a significant predictor of the growth potential, while the fruit type and storage temperature were not.

scholarly journals Evaluation of different oxygen, carbon dioxide and nitrogen combinations employed to extend the shelf life of fresh-cut collard greens

2003 ◽  
Vol 21 (4) ◽  
pp. 676-680 ◽  
Author(s):  
Celso L. Moretti ◽  
Alessandra L. Araújo ◽  
Leonora M. Mattos
Keyword(s):  
Vitamin C ◽  
Storage Period ◽  
Soluble Solids ◽  
Total Chlorophyll ◽  
Minimally Processed ◽  
Total Vitamin ◽  
Collard Greens ◽  
Fresh Cut ◽  
Solids Content ◽  
And Control

Collard greens (Brassica oleracea var. acephala) "Manteiga" were harvested in commercial fields in Brasilia, Brazil, aiming to evaluate different oxygen, carbon dioxide and nitrogen combinations to extend the shelf life of the fresh-cut product. After harvest, leaves were taken to the postharvest laboratory, selected for external blemishes and minimally processed (3 mm thick) inside a cold room (13±2°C). After processing, fresh-cut collard greens were stored under two controlled atmosphere (CA) conditions (3% O2, 4% CO2; 5% O2, 5% CO2/balance N2), and normal air (control), at 5°C (95±2% RH), for six days. Daily, minimally processed collard greens were evaluated for total vitamin C, total chlorophyll, total soluble solids content, and titratable acidity. Total vitamin C content decreased for all treatments during the storage period. Storage under CA conditions delayed total vitamin C degradation for both atmospheres studied. At the end of the storage period, fresh-cut collard greens stored under 3% O2, 4% CO2 showed around 25% and 56% more vitamin C than the material stored under 5% O2, 5% CO2 and control, respectively. Total chlorophyll content decreased during the storage period. At the end of the experiment, fresh-cut collard greens stored under 3% O2, 4% CO2 showed 24% and 45% more total chlorophyll than the product stored under 5% O2, 5% CO2 and control, respectively. CA storage delayed organic acid degradation. On the sixth day, fresh-cut collard greens stored under 3% O2, 4% CO2 presented around 44% more organic acids than control. Total soluble solids content were not significantly affected.

Prevalence and level of Listeria monocytogenes and other Listeria sp. in ready-to-eat minimally processed and refrigerated vegetables

2012 ◽  
Vol 29 (4) ◽  
pp. 707-712 ◽  
Author(s):  
Mira Kovačević ◽  
Jelena Burazin ◽  
Hrvoje Pavlović ◽  
Mirela Kopjar ◽  
Vlasta Piližota
Keyword(s):  
Listeria Monocytogenes ◽  
Minimally Processed

Effect of Gamma Radiation on the Reduction of Salmonella strains, Listeria monocytogenes, and Shiga Toxin–Producing Escherichia coli and Sensory Evaluation of Minimally Processed Spinach (Tetragonia expansa)

2014 ◽  
Vol 77 (10) ◽  
pp. 1768-1772 ◽  
Author(s):  
ANA CAROLINA B. REZENDE ◽  
MARIA CRYSTINA IGARASHI ◽  
MARIA TERESA DESTRO ◽  
BERNADETTE D. G. M. FRANCO ◽  
MARIZA LANDGRAF
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Gamma Radiation ◽  
Shiga Toxin ◽  
Radiation Doses ◽  
Minimally Processed ◽  
Tetragonia Expansa ◽  
Effects Of Irradiation On ◽  
Spinach Leaves

This study evaluated the effects of irradiation on the reduction of Shiga toxin–producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10-values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

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