Influence of fruit matrix and storage temperature on the survival of Listeria monocytogenes in a gastrointestinal simulation (original) (raw)
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Behavior of Listeria Monocytogenes and Escherichia Coli O157:H7 in Fresh-Sliced Cactus-Pear Fruit
Journal of Food Safety, 2005
Storage experiments were conducted to follow the behavior of Listeria monocytogenes and Escherichia coli O157:H7, deliberately inoculated on fresh-cut cactus-pear fruits before packaging under modified and control atmosphere and stored at four different temperatures (4, 8, 12 and 20C). L. monocytogenes was able to proliferate during storage at different temperature both in control and modified atmosphere. By comparing the sanitary-risk values with those of shelf life, it is possible to conclude that the storage of cactus-pear samples at temperatures greater than 4C, both in control and in modified atmospheres, could lead to a significant health-time risk, and that this is strictly affected by temperature. E. coli O157:H7 was able to proliferate only in the sample stored at 4 and 8C in both package atmospheres. On the contrary, this species was completely suppressed at the higher temperatures. In our study, E. coli O157:H7 appeared to be much less suited for survival on the surface of the fruit than L. monocytogenes.
Food Control, 2017
During the fall of 2014, commercially produced prepackaged caramel apples were linked to 35 cases of listeriosis in 12 states. In response, this study aimed to assess 1) the reduction of different outbreak and non-outbreak strains of Listeria monocytogenes during caramel dipping of apples, and 2) subsequent growth of the apple outbreak strains within caramel apples during storage at 22 and 4 C. In aim 1, three unwaxed Jonathan apples were dip-inoculated with three different 4-strain L. monocytogenes cocktails (apple outbreak, unrelated outbreak or unrelated environmental) at~8 log CFU/apple, dried for 1 h, dipped for 5 s in caramel at 82, 88, 93 or 99 C, cooled for 1 h at room temperature and assessed for survivors. In aim 2, Jonathan apples were spot-inoculated with the apple outbreak cocktail (~3 log CFU/ apple) at the stem juncture, dried for 1 h, pushed onto wooden sticks, and dipped in caramel at 82 C. During storage at 4 and 22 C for 28 and 14 days, respectively, four different apple sections (top, middle, bottom and core) were cut from three apples, homogenized and plated for Listeria. After dipping apples in caramel at 82 and 99 C, the apple outbreak, unrelated outbreak and environmental Listeria strains decreased 2.0 ± 0.6 and 2.7 ± 0.1, 1.8 ± 0.3 and 2.6 þ 0.1, and 1.7 ± 0.1 and 2.9 ± 0.2 logs, respectively, with the environmental cocktail significantly less heat resistant (P < 0.05) at 99 C compared to the other two cocktails. After 14 days of storage at 22 C, Listeria populations were significantly higher (P < 0.05) in the core (7.4 ± 0.6 log CFU/g) compared to the other three sections (4.9e5.4 log CFU/g). The same trend was seen for the core (7.7 ± 0.6 log CFU/g) and the other three sections (5.0e5.4 log CFU/g) after 28 days of storage at 4 C. Since dipping in hot caramel cannot ensure pathogen elimination, producers of caramel apples should implement good agricultural practices, post-harvest preventive controls and refrigeration of the final product to minimize the risks from Listeria.
AGRITEKNO, Jurnal Teknologi Pertanian, 2017
The increasing demand of minimally processed fruits and vegetables signify a challenge to make them stable and safe to be consumed. The processing of this type of product may contribute higher risks of food borne illnesses. One of the foodborne pathogens in minimally processed fruits and vegetables is Listeria monocytogenes. The importance of understanding the characteristics of L. monocytogenes will help to determine how this microorganism occurs, grows, and survives in minimally processed fruits and vegetables. Proper and suitable methods to reduce L. monocytogenes so that it can not pose a significant risk to cause disease therefore are able to be determined according to the model of the growth and survival of L. monocytogenes in minimally processed fruits and vegetables.
Survival of Listeria Monocytogenes in Tomato Juice at 5 and 30°C Storage
Current research in nutrition and food science
Listeria monocytogenes is a food-borne pathogen and has been associated with a variety of food products including fruits and vegetables, which are important for a healthy human diet. L. monocytogenes survives and grows at low temperatures and thus it can be multiplied to dangerous levels in a product which is kept at refrigeration temperatures. This work examines the ability of L. monocytogenes to survive, in a product of high consumption frequency, such as tomato juice, in correlation to storage temperature. The results indicate that a significant number of cells survived in tomato juice whether the storage temperature was 30°C or 5°C, although the refrigerator temperature slightly reduces the survival of L. monocytogenes cells. An understanding of the cold stress response of the pathogen will be helpful in the design of effective methods to control L. monocytogenes in freezing foods in order to provide consumers with a safe product.
Fate of Listeria monocytogenes in Fresh Apples and Caramel Apples
Journal of Food Protection, 2016
An outbreak of listeriosis in late 2014 and early 2015 associated with caramel apples led to questions about how this product became a vector for Listeria monocytogenes. This investigation aimed to determine information about the survival and growth of L. monocytogenes in both fresh apples and caramel apples, specifically examining the effects of site and level of inoculation, inoculum drying conditions, and storage temperature. At a high inoculation level (7 log CFU per apple), L. monocytogenes inoculated at the stem end proliferated on Gala caramel apples at both 5 and 25°C and on Granny Smith caramel apples at 25°C by as much as 3 to 5 log CFU per apple. Fresh apples and caramel apples inoculated at the equatorial surface supported survival but not growth of the pathogen. Growth rates (μmax) for apples inoculated at the stem end, as determined using the Baranyi and Roberts growth model, were 1.64 ± 0.27 and 1.38 ± 0.20 log CFU per apple per day for Gala and Granny Smith caramel a...
International Journal of Environmental Research and Public Health
Recent recalls of stone fruit due to potential Listeria contamination and associated foodborne outbreaks highlight the risk for pathogen transmission through stone-fruit consumption. Particularly, surface contamination of fruits increases the risk for cross-contamination of produce during processing and storage. This highlights the need for quality control in stone fruits intended for consumption. To develop effective food safety practices, it is essential to determine the critical factors during stone-fruit processing that influence Listeria survival. Therefore, this study evaluated the ability of Listeria to survive on peaches and nectarines under simulated stone-fruit loading and staging, waxing and fungicide application and storage conditions. The results of our study indicate that current stone-fruit handling conditions do not favor Listeria growth. However, once fruit is contaminated, Listeria can survive on the fruit surface in significant numbers under current processing con...
Food Control, 2009
The aim of this work was to study the growth/survival of acid-adapted cells of Listeria monocytogenes, in orange juice and in minimally processed orange slices. The L. monocytogenes OML 45 behaviour into TSB (Tryptic Soy Broth) medium was evaluated at different pH values (between 3.7 and 6.7). The acid-adapted cells were obtained maintaining L. monocytogenes in TSB at pH 5.7 for 3 h. The obtained cells were then inoculated into a diluted orange juice with a pH of 2.6. Moreover, the acid-adapted cells were inoculated into minimally processed orange slices. The growth was evaluated during storage at different temperatures. The study confirms that orange juice and minimally processed orange slices can support the acid-adapted pathogen growth.
Food Microbiology, 2004
Hot water may be used to kill Listeria monocytogenes on frankfurters immediately before consumption. This study evaluated the effectiveness of different time and water temperature combinations in destroying L. monocytogenes on frankfurters formulated with or without potassium lactate and sodium diacetate (PL/SD). Frankfurters were inoculated (1-2 log CFU/cm 2 ), vacuum-packaged and stored at 4°C (manufacturer/retail conditions). On days 18, 40 and 60, packages were opened, reclosed and stored at 7°C (household conditions). At 0, 7 and 14 days of simulated household storage, frankfurters were exposed to hot water (80 or 94°C) that was either maintained at constant temperature or removed from the heat source. The 80°C (60, 120 s) and 94°C (30, 60 s) treatments reduced pathogen counts on frankfurters with PL/SD to the detection limit (-0.4 log CFU/cm 2 ) or below from initial levels of 0.6-0.9 log CFU/cm 2 . For frankfurters without PL/SD, where pathogen numbers on the control reached 5.3 log CFU/cm 2 , hot water treatments reduced counts by 0.3 (80°C, 30 s) to > 5.7 (94°C, 300 s) log CFU/cm 2 . No survivors were detected in the heated water after any treatment. Findings of this study may be useful for the development of science-based recommendations for reheating of frankfurters by consumers in their homes.
A Review: Gaseous Interventions for Listeria monocytogenes Control in Fresh Apple Cold Storage
Frontiers in Microbiology, 2021
Listeria monocytogenes (L. monocytogenes) causes an estimated 1600 foodborne illnesses and 260 deaths annually in the U.S. These outbreaks are a major concern for the apple industry since fresh produce cannot be treated with thermal technologies for pathogen control before human consumption. Recent caramel apple outbreaks indicate that the current non-thermal sanitizing protocol may not be sufficient for pathogen decontamination. Federal regulations provide guidance to apple processors on sanitizer residue limits, organic production, and good manufacturing practices (GMPs). However, optimal methods to control L. monocytogenes on fresh apples still need to be determined. This review discusses L. monocytogenes outbreaks associated with caramel apples and the pathogen’s persistence in the environment. In addition, this review identifies and analyzes possible sources of contaminant for apples during cold storage and packing. Gaseous interventions are evaluated for their feasibility for ...
Internalization of Listeria monocytogenes in Whole Avocado
Journal of food protection, 2016
In recent years, tree fruits have emerged as a new concern for Listeria monocytogenes contamination. The objective of the current study was to evaluate the potential internalization of L. monocytogenes from the surface of avocados into the edible portions of the fruit during certain postharvest practices simulated in a laboratory setting. One set of intact avocados was spot inoculated with L. monocytogenes on the stem scar, and the second set was hydrocooled in water contaminated with L. monocytogenes. Under these experimental conditions, L. monocytogenes internalized into the avocado pulp through the stem or stem scar after both spot inoculation and hydrocooling. In avocados spot inoculated with 50, 130, 500, and 1,300 CFU per fruit, bacteria were detected in the edible portion adjacent to the stem scar within 15 days postinoculation during storage at 4°C. In avocados hydrocooled in water containing L. monocytogenes at 10(6) and 10(8) CFU/ml, bacteria reached the bottom end of the ...