Category Archives: Food Technology

Guidelines – Hygiene guidelines for the control of Listeria monocytogenes in the production of quick-frozen vegetables.

Posted on December 10, 2020 by | Leave a comment

PROFEL

Abstract
A multidisciplinary approach is recommended to control the environmental pathogen Listeria monocytogenes in the production of quick-frozen vegetables. A food safety management system, based on Pre-Requisite Programs (PRPs, focusing on the hygiene and organization of the production environment) and a HACCP-plan (focusing on the process control), need to have a full focus on Listeria monocytogenes in order to prevent the organism from colonizing and persisting in complex biofilm formations, or to prevent contamination with the organism after (thermal) processing during further handling before packaging. Figure 1 illustrates the different PRPs and the HACCP-plan relevant in the prevention and control of Listeria monocytogenes. Environmental control needs to be established in order to verify the effectiveness of the implemented PRPs and HACCP-plan and to evaluate the potential accumulation of Listeria monocytogenes in the broader production environment. Finally, end product specifications must help Food Business
Operators (FBOs) to set intermediate levels towards L. monocytogenes, achievable in end products when a proper food safety management system is in place. Risk communication and information sharing towards the users of quick-frozen vegetables must clearly state the proper use of the frozen products to avoid potential abuse. Apart from these technomanagerial activities, an FBO also needs to establish a safety culture and create awareness throughout the whole production organization and all its aspects in the prevention and control of food safety hazards and hygiene disruptions.
The presented guidelines cover frozen vegetables, blanched and unblanched, which are considered as Non Ready-To- Eat (nRTE). FBOs intending to market frozen vegetables as Ready-To-Eat (RTE), would also benefit from following these guidelines. Such FBOs, however, should follow additional preventive and control measures to assure the safety of RTE products, but these are not included in the current guidelines.

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Technology, Food Testing, Listeria, Listeria monocytogenes, Research, Uncategorized

Research – Use of a Novel Sanitizer To Inactivate Salmonella Typhimurium and Spoilage Microorganisms during Flume Washing of Diced Tomatoes

Posted on December 4, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

As demand for fresh-cut produce increases, minimizing the risk of salmonellosis becomes critical for the produce industry. Sanitizers are routinely used during commercial flume washing of fresh-cut produce to minimize cross-contamination from the wash water. This study assessed the efficacy of a novel sanitizer blend consisting of peracetic acid (PAA; OxypHresh 15) with a sulfuric acid–surfactant (SS) antimicrobial (PAA-SS; ProduceShield Plus) against Salmonella during simulated commercial washing of diced tomatoes. Triplicate 9.1-kg batches of Roma tomatoes were dip inoculated in a two-strain avirulent Salmonella cocktail (Salmonella Typhimurium LT2 and MHM112) to achieve 5 to 6 log CFU per tomato and air dried for 2 h. After mechanical dicing, the tomatoes were washed in a pilot-scale processing line for 60 s with or without an added organic load in 90 ppm of PAA-SS (pH 1.8), SS at pH 1.8, 90 ppm of PAA, 5 or 10 ppm of free chlorine or sanitizer-free water as the control. Overall, PAA-SS (1.75 ± 0.75 log CFU/g) was significantly (P ≤ 0.05) more effective than water (0.69 ± 0.42 log CFU/g), chlorine (0.35 ± 0.36 log CFU/g), or SS (0.36 ± 0.19 log CFU/g) in reducing Salmonella. After washing for 20 s, PAA-SS was the only sanitizer to show a significant (P ≤ 0.05) reduction (1.93 ±0.59 log CFU/g) in Salmonella. All wash water samples were negative for Salmonella, except for 5 and 10 ppm of chlorine and the water control. Using PAA-SS with an organic load, yeast and mold populations were below the limit of detection (1.40 log CFU/g) and significantly (P ≤ 0.05) lower on diced tomatoes after 14 days of refrigerated storage compared with the other treatments (8.37 ± 0.08 log CFU/g), with SS at pH 1.8 (3.91 ± 0.93 log CFU/g) most effective against yeast and mold in the absence of an organic load. On the basis of these findings, the safety and shelf life of commercially washed diced tomatoes can be improved with PAA-SS.

HIGHLIGHTS
  • PAA-SS yielded lower Salmonella populations in diced tomatoes than did chlorine (P ≤ 0.05).
  • Salmonella was not detected in the wash water using PAA-SS.
  • PAA-SS decreased Salmonella 1.93 log after 20 s of washing.
  • PAA-SS yielded lower (P ≤ 0.05) yeast and mold populations after 14 days of storage.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Research, Salmonella, Technology

Research – Reduction of Norovirus in Foods by Nonthermal Treatments: A Review

Posted on December 4, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

Human noroviruses are enteric pathogens that cause a substantial proportion of acute gastroenteritis cases worldwide regardless of background variables such as age, ethnicity, and gender. Although person-to-person contact is the general route of transmission, foodborne infections are also common. Thorough cooking eliminates noroviruses, but several food products such as berries, leafy vegetables, and mollusks undergo only limited heat treatment, if any, before consumption. Novel applications of nonthermal processing technologies are currently being vigorously researched because they can be used to inactivate pathogens and extend product shelf life with limited effects on nutrient content and perceived quality. These technologies, adopted from several industrial fields, include some methods already approved for food processing that have been applied in the food industry for years. However, a majority of the research has been conducted with bacteria and simple matrixes or surfaces. This review focuses on elimination of norovirus in food matrixes by use of nonthermal technologies in four categories: high hydrostatic pressure, light, irradiation, and cold atmospheric plasma. We discuss the properties of noroviruses, principles and inactivation mechanisms of select technologies, and main findings of relevant studies. We also provide an overview of the current status of the research and propose future directions for related work.

HIGHLIGHTS
  • High pressure processing is the most promising nonthermal treatment for noroviruses.
  • High pressure processing, ionizing radiation, and UVC light can reduce noroviruses in foods.
  • Treatments used to eliminate viruses can impair food product quality.
  • Optimal virus elimination strategies should be validated independently for each food product.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Food Virus, microbial contamination, Microbiology, Norovirus, Research, Technology, Virus

Research – Effect of Blanching on Aflatoxin Contamination and Cross-Contamination of Almonds

Posted on December 4, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

Blanching of almonds was examined for reducing the aflatoxin content of contaminated nuts. Almonds with intact pellicles were spiked with aflatoxin B1 (AFB1) and blanched at 85°C. Following blanching, almond kernels and pellicles contained 20 and 19% of the spiked AFB1, respectively. The blanching water contained an additional 41% of the spiked AFB1. In a separate study, postblanching water was spiked with AFB1 and used for subsequent blanching of uncontaminated almonds. The resulting blanched kernels acquired 3.3% of the AFB1 from the spiked water, demonstrating a low level of cross-contamination from reused contaminated blanching water. The effect of the blanching temperature on partitioning of AFB1 from almonds to blanching water was significant at a 20-ppb spiking level, but not at 100 ppb. AFB1 levels that were unaccounted for in the mass balance of blanching components were presumed to be lost due to binding to water-solubilized almond components and were independent of pH and blanching time. Blanching reduced total aflatoxins in naturally contaminated almonds by 13 to 76%, depending on almond quality, as well as blanching time and temperature. These results indicate that the association between almond components and aflatoxin generated through mold contamination is more complex than in spiking experiments.

HIGHLIGHTS
  • Blanching and pellicle removal reduced aflatoxin in spiked almonds by up to 80%.
  • Low-level cross-contamination occurred in almonds blanched in contaminated water.
  • Aflatoxin reduction in naturally contaminated almonds by blanching was variable.

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Posted in Aflatoxin, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Poisoning, Food Safety, Food Technology, Food Testing, Food Toxin, Mold Toxin, Mould Toxin, Mycotoxin, Toxin

Research – Practical application of bacteriophage in food manufacturing facilities for the control of Listeria sp.

Posted on December 3, 2020 by | Leave a comment

Wiley Online

Listeria monocytogenes is a foodborne pathogen with the ability to persist and form biofilm matrices in processing environments of food manufacturing facilities. Bacteriophages are bacterial viruses with host specific lethality. Published research on the application of phage to control Listeria sp. in manufacturing environments is limited. In this study, we have assessed the capacity of bacteriophage P100 (Listex™) to reduce incidence of Listeria sp. in the ready‐to‐eat (RTE) environment of refrigerated (4°C) and ambient (20°C) temperature facilities using two different application strategies. A moderate application applied as a single treatment every 24 hr over three days (2 × 107 PFU/ml) and an intensified application applied once every 6 hr over a 24 hr period (1 × 108 PFU/ml). Environmental nonfood contact surface (NFCS) samples were collected and analyzed for the presence of Listeria sp. before and after treatment. When the moderate treatment protocol was applied the incidence of positives decreased from 51.3 to 17.5% in the 4°C environment and from 67.5 to 23.1% in the 20°C production area. For the intensified phage treatment method, the initial positive rate in the 4°C environment ranged from 5 to 47.5%, with an overall 43% reduction in Listeria sp. In the 20°C facility, initial environmental Listeria sp. ranged from 15 to 50%, with an overall reduction of 32% after treatment with phage P100. Data indicate the application of Listeria specific phage P100 in RTE food production environments by either the moderate or intensified application method can reduce incidence and be considered an additional intervention strategy for controlling this pathogen on NFCS.

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Posted in Biofilm, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Technology

Research – Preharvest Treatment Improves Tomato Food Safety

Posted on December 1, 2020 by | Leave a comment

Technology Networks

cherry-tomato-pristine-variety

When vegetable farmers harvest crops, they often rely on postharvest washing to reduce any foodborne pathogens, but a new University of Georgia study shows promise in reducing these pathogens — as well as lowering labor costs — by applying sanitizers to produce while it is still in the fields.

Salmonella, Shiga toxin-producing E. coli and Listeria monocytogenes are major causes of foodborne diseases and of public health concern in the U.S. Tomato-associated salmonella outbreaks reported to the Centers for Disease Control and Prevention have increased in frequency and magnitude in recent years, and fresh produce accounted for 21% of E. coli outbreaks reported to the CDC over a 20-year span.

Initially researchers were going to study the use of a nonchlorine-based sanitizer made of two food additives approved by the U.S. Food and Drug Administration — levulinic acid and sodium dodecyl sulfate — as a postharvest wash solution. However, at the suggestion of a producer involved in the study — Bill Brim of Lewis Taylor Farms in Tifton, Georgia — they designed the study using the solution in a preharvest spray, said Tong Zhao, associate research scientist with the Center for Food Safety on the UGA Griffin campus.

While producers commonly use chlorine-based disinfectants — including chlorine gas, sodium hypochlorite, calcium hypochlorite and chlorine dioxide — to treat produce postharvest, the preharvest application of bactericides is not a common practice, Zhao said.

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Posted in Bacteria, bacterial contamination, E.coli, food contamination, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Poisoning, Food Safety, Food Technology, Listeria, Listeria monocytogenes, Research, Salmonella, STEC, STEC E.coli

Research – Source attributed case-control study of campylobacteriosis in New Zealand

Posted on November 30, 2020 by | Leave a comment

IJID

Campylobacter kswfoodworld

Image CDC

Background

Following an initial reduction in human campylobacteriosis in New Zealand after the implementation of poultry food chain-focused interventions during 2006–2008, further decline has been relatively small.
We report a year-long study of notified campylobacteriosis cases, incorporating a case control study combined with a source attribution study. The purpose was to generate up-to-date evidence on the relative contributions of different sources of campylobacteriosis in New Zealand.

Methods

The study approach included: A case-control study of notified cases (aged six months or more) sampled in a major urban centre (Auckland, every second case) and a mixed urban/rural area (Manawatū/Whanganui, every case), between 12 March 2018 and 11 March 2019.
Source attribution of human campylobacteriosis cases sampled from these two regions over the study period by modelling of multilocus sequence typing data of Campylobacter jejuni and C. coli isolates from faecal samples of notified human cases and relevant sources (poultry, cattle, sheep).

Results

Most cases (84%) were infected with strains attributed to a poultry source, while 14% were attributed to a cattle source. Approximately 90% of urban campylobacteriosis cases were attributed to poultry sources, compared to almost 75% of rural cases.
Poultry consumption per se was not identified as a significant risk factor. However specific risk factors related to poultry meat preparation and consumption did result in statistically significantly elevated odds ratios.

Conclusions

The overall findings combining source attribution and analysis of specific risk factors indicate that poultry meat remains a dominant pathway for exposure and infection.

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Posted in Campylobacter, food contamination, food handler, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Technology, Food Testing, Research

Research – Reducing Campylobacter jejuni, Enterobacteriaceae, Escherichia coli, and total aerobic bacteria on broiler carcasses using combined ultrasound and steam

Posted on November 28, 2020 by | Leave a comment

Journal of Food Protection

Campylobacter kswfoodworld

Campylobacteriosis is the most frequently reported foodborne illness in Europe and many other parts of the world. Campylobacter can colonize the intestines of broilers, most often in large amounts. Broilers are usually slaughtered in a high-speed automated system that can rupture the intestines during evisceration, resulting in contamination of carcasses with intestinal bacteria such as Campylobacter. This study evaluated the combined effect of ultrasound and steam (SonoSteam®) on naturally contaminated chicken carcasses at a large-scale abattoir in Sweden. Ultrasound at 30-40 kHz and steam at 84-85 °C or 87-88 °C was used at slaughter with a line speed of 18 000 birds per hour. The amount of Campylobacter spp., Enterobacteriaceae , Escherichia coli , and total aerobic bacteria on neck skins from 103 chicken carcasses, sampled before and after treatment by SonoSteam, was analyzed.Campylobacter spp. was detected in 58 (56%) of the 103 neck skins, from birds belonging to four of the seven flocks represented. All 58 isolates were identified as Campylobacter jejuni . After the SonoSteam treatment, a mean reduction in C. jejuni, Enterobacteriaceae, E. coli and total aerobic bacteria were log 0.5 ± 0.8, log 0.6 ± 0.6, log 0.5 ± 0.6, log 0.4 ± 0.7 CFU/g respectively. No significant differences in reduction between the two different treatment temperatures was observed for any of the bacteria.Although the bacterial reductions were significant, large amounts of bacteria remained on the carcasses after treatment. Further studies are needed to identify optimal measures at slaughter to reduce food spoilage bacteria and pathogenic bacteria, which should be considered in a One Health perspective.

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Posted in E.coli, Enterobacteriaceae, Food Microbiology Research, Food Technology, Research

Research – Quantification of survival and transfer of Salmonella on fresh cucumbers during waxing

Posted on November 28, 2020 by | Leave a comment

Journal of Food Protection

Cucumbers found in retail markets are often waxed to improve visual appeal and retard moisture loss. This waxing may affect bacterial survival and the waxing process may facilitate cross-contamination between cucumbers. This study assessed survival of Salmonella on waxed and un-waxed cucumbers and the potential for Salmonella cross-contamination during the waxing process. Fresh waxed or un-waxed cucumbers were spot-inoculated with a Salmonella enterica cocktail. Three different wax coatings (mineral oil, vegetable oil, or petroleum wax) were manually applied to un-waxed cucumbers using polyethylene brushes. Salmonella transfer from inoculated cucumbers to brush or to un-inoculated cucumbers was quantified. Higher Salmonella concentrations were observed on waxed cucumbers during the first 3 days of storage but the final concentration on un-waxed cucumbers was higher than on waxed cucumbers at the end of storage, regardless of storage temperature. Wax formulation did affect survival of Salmonella inoculated directly into waxes, with the significant decline in Salmonella populations observed in vegetable-based wax coating, but with populations unchanged over 7 days at 7 or 21 °C in mineral oil-based and petroleum-based waxes. Salmonella cells could transfer from inoculated un-waxed cucumbers to brushes used for waxing and then to un-inoculated cucumbers during waxing. Significantly higher log percent transfer to brushes was observed when cucumbers were waxed with vegetable oil (0.71 log percent, P = 0.00441) vs. mineral oil (0.06 log percent) or petroleum (0.05 log percent). Transfer to un-inoculated cucumbers via brushes was also quantified (0.18 to 0.35 log percent transfer). Salmonella remaining on contaminated cucumbers after waxing could be detected for up to 7 days, and Salmonella survived better on cucumbers treated with a petroleum-based wax. These findings should be useful in managing risk of Salmonella contamination in cucumbers during post-harvest handling.

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Posted in food contamination, food handler, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Technology, Research, Salmonella, Technology

Research – Anti‐adhesive effects of sialic acid and Lactobacillus plantarum on Staphylococcus aureus in vitro

Posted on November 24, 2020 by | Leave a comment

Journal of Food Safety

Staphylococcus aureus (S. aureus) is a common food‐borne pathogen that causes severe diseases after adhesion to epithelial cells. Lactobacillus inhibits pathogenic bacterial adhesion and infection. In addition, sialic acid (SA) is widely known for its beneficial biological functions. A new way of reducing the occurrence of diseases and curbing the overuse of antibiotics is ingesting prebiotics and probiotics that regulate the intestinal flora. In this study, we first evaluated the anti‐adhesive effects of several strains of Lactobacillus on S. aureus. The study revealed that the S. aureus adhesion was inhibited by all the strains of Lactobacillus. Besides, the rate of inhibition by L. plantarum Z‐4 was significantly higher than other Lactobacillus species. We then investigated the effects of different SA concentrations (40, 100, 150, 200, and 260 μg/ml) on the growth and adhesion characteristics of L. plantarum and S. aureus. The results showed that SA influences bacterial adhesion by regulating the bacteria’s growth characteristics. Finally, the effects of SA combined with Lactobacillus on the adhesion of S. aureus were assessed by competition, exclusion and displacement methods. SA with a concentration of 260 μg/mL combined with L. plantarum had the highest inhibition effect on the competition assays. In addition, the expression of S. aureus adhesion‐related genes was reduced. This provides a new perspective on the application of SA and/or L. plantarum and its potential to resist adhesion of S. aureus.

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Posted in food contamination, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Technology, Food Testing, Lactobacillus plantarum, Research, Staphylococcus aureus, Technology