Behavior of Listeria Monocytogenes and Escherichia Coli O157:H7 in Fresh-Sliced Cactus-Pear Fruit (original) (raw)
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Food Control, 2017
This study aimed to assess the effect of storage temperature and fruit matrix on the survival of L. monocytogenes after a gastrointestinal simulation. The growth of L. monocytogenes on different matrices (fresh-cut pear and melon and synthetic growth medium as a control) and storage temperature (1, 5, 10 and 20 °C) was evaluated. Subsequently, the ability of the pathogen on different fruit matrices to overcome the gastrointestinal simulation was evaluated. The highest reduction in the population of L. monocytogenes on fresh-cut pear and melon subjected to the gastrointestinal simulation was after 6 days of storage at 5 °C (0.84 and 2.12 log reduction on the pear and melon, respectively). Conversely, higher survival ratios of L. monocytogenes in both matrices were observed at 1 °C, even with logarithmic increases after the whole gastrointestinal simulation during the experiment. At 20 °C, the survival capacity of L. monocytogenes was higher than that under storage at 5 and 10 °C when grown on fresh-cut pear, whereas this was not observed on fresh-cut melon. In general, under the proper storage temperature of fresh-cut fruit (5 °C) and after 1 day of storage, the L. monocytogenes on the melon was more sensitive than that on the pear, and this behaviour was maintained for up to 9 days. The ability of L. monocytogenes to overcome the gastrointestinal tract was not enhanced when the pathogen grew on fresh-cut pear and melon under the proper storage temperature.
Food Microbiology, 2010
Consumption of fresh-cut produce has sharply increased recently causing an increase of foodborne illnesses associated with these products. As generally, acidic fruits are considered 'safe' from a microbiological point of view, the aim of this work was to study the growth and survival of Escherichia coli O157:H7, Salmonella and Listeria innocua on minimally-processed peaches. The three foodborne pathogens population increased more than 2 log 10 units on fresh-cut peach when stored at 20 and 25 C after 48 h. At 10 C only L. innocua grew more than 1 log 10 unit and it was the only pathogen able to grow at 5 C. Differences in growth occurred between different peach varieties tested, with higher population increases in those varieties with higher pH ('Royal Glory' 4.73 AE 0.25 and 'Diana' 4.12 AE 0.18). The use of common strategies on extending shelf life of fresh-cut produce, as modified atmosphere packaging and the use of the antioxidant substance, ascorbic acid (2% w/v), did not affect pathogens' growth at any of the temperatures tested (5 and 25 C). Minimally-processed peaches have shown to be a good substrate for foodborne pathogens' growth regardless use of modified atmosphere and ascorbic acid. Therefore, maintaining cold chain and avoiding contamination is highly necessary.
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.
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.
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.
Journal of Food Protection, 2016
Temperature and good sanitation practices are important factors for controlling growth of microorganisms. Fresh produce is stored at various temperatures to ensure quality and to prolong shelf life. When foodborne pathogens survive and grow on fresh produce at storage temperatures, then additional control strategies are needed to inactivate these pathogens. The aim of this study was to determine how temperatures associated with deciduous fruit processing and storage facilities (0.5, 4, and 21°C) affect the growth and/or survival of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica subsp. enterica serovar Typhimurium, and Staphylococcus aureus under different nutrient conditions (nutrient rich and nutrient poor) and on simulated contact surfaces (vinyl coupons). Information on the growth and survival of foodborne pathogens at specific deciduous fruit processing and storage temperatures (0.5°C) is not available. All pathogens except E. coli O157:H7 were able to sur...
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 ...
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...
2015
FATE OF LISTERIA MONOCYTOGENES IN DICED ONIONS, AND CELERY, AND SALMONELLA TYPHIMURIUM IN DICED TOMATOES, IN DIFFERENT PACKAGING SYSTEMS DURING SIMULATED COMMERCIAL STORAGE By Victor Oladimeji Jayeola Temperature is arguably the most important factor affecting microbial proliferation in fresh-cut produce. In this study, the growth responses of Listeria Monocytogenes in diced onions and celery, and Salmonella Typhimurium in diced tomatoes in modified atmosphere packages and snap-fit containers were examined using three fluctuating time/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 the products stored under the profiles with the highest and intermediate temperature abuse showing significant growth (P < 0.05) in all packages. Salmonella Typhimurium did not show any significant growth in diced tomatoes under the three temperature conditions cons...
Journal of Food Protection, 2021
Recent apple-related recall and outbreak events have exposed a need for better food safety controls along the supply chain. Following harvest apples can be stored under a controlled atmosphere for up to one year after harvest before packing and distribution, making the crop susceptible to many opportunities for contamination that increase the quantity of postharvest losses. Botrytis cinerea (BC) and Penicillium expansum (PE) cause significant rot-associated losses to the apple industry. These fungi can colonize and destroy apple tissue as storage duration increases, which may also impact the growth of saprophytic foodborne pathogens like Listeria monocytogenes . Thus the objective of this study was to observe population changes of Listeria innocua (LI) as a surrogate for L. monocytogenes on apples inoculated with BC or PE under long-term controlled atmosphere cold storage conditions to identify the effect of postharvest mold growth on growth patterns of a food safety-relevant microo...