Posts from the "Research News" category

UW Researchers Make Discovery in Fight Against Food Pathogen University of Wyoming researchers have discovered a substance that greatly increases the survival of listeria monocytogenes.
Researchers hope the discovery will lead to the development of techniques to better combat the pathogen and to improve food safety.
Mark Gomelsky, a professor in UW’s Department of Molecular Biology, and other researchers discovered and characterized a substance, called exopolysaccharide (EPS), that listeria secretes on its cell surface under certain conditions. The EPS coats bacterial cells and makes them form aggregates or clumps, which are strongly protected from commonly used disinfectants and desiccation (extreme drying).
“We think that EPS plays a significant role in survival of listeria in the environment, during food storage, processing and transportation,” Gomelsky says.
Read the full article at the University of Wyoming website

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So what do consumers really think about food safety?

“67 percent of the 5000 people surveyed believed that food safety was essential, compared to only 48 percent seven years ago.”

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Reading food safety advice on labels

Consumer understanding of food safety on labels advice is improving but there is still room for improvement.

There has been a lot of interest in recent years about how consumers understand and use the nutrition information on food labels to assist them in making healthier food choices. However, the food safety components on food labels, such as ‘use by’ and ‘best before’ dates, as well as cooking and storage instructions, have received less attention. This is despite the fact that this labelling, if followed correctly, plays an important role in reducing the risk of foodborne illness.

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Chemicals and Food Safety

Confused by the chemical jargon? Don’t understand the registration process?

Agricultural chemicals, whether they be for conventional production systems, organic production systems or both, must be registered by the Australian Pesticides and Veterinary Medicines Authority (APVMA) before they can be legally supplied, sold or used in Australia.

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Study traces E.coli toll from bagged salads

About 63,000 cases of illness from E.coli happen in the U.S. each year, and a growing number of cases are linked to lettuce, spinach and other leafy greens in bagged salads, according to a study published in the journal Foodborne Pathogens and Disease. The study examined an outbreak of foodborne illness that was traced to bagged salad, in which six people were hospitalized and two died.

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Decontamination by ultrasound application in fresh fruits and vegetables

Ever wondered about how ultrasound could be used to enhance food safety? An article to be published in Food Safety details the “principles, mechanisms and effects of ultrasound on fruits and vegetables as a sanitization technology.”

Changes in consumer eating habits, health concerns, and convenient and practical foods have led to an increased demand for fruit and vegetable products. Food safety is essential considering that there are reports of outbreaks involving the consumption of fruits and vegetables contaminated with pathogens. Washing associated with sanitizer procedure is considered as a critical step to satisfy hygienic and sanitary requirements and maintain the sensory and nutritional characteristics of fruits and vegetables. Chemical compounds are widely applied to clean and sanitize fresh fruits and vegetables, and some of these chemicals, such as the inorganic chlorine compounds, produce by-products that are dangerous to human health. The use of ultrasound is a technology that is gaining ground in the food industry. Ultrasound is a form of energy generated by sound waves at frequencies that are too high to be detected by the human ear. In ultrasound, the removal of dirt and food residues from surfaces and the inactivation of microorganisms occur as a consequence of cavitation, which is the formation, growth and collapse of bubbles that generate a localized mechanical and chemical energy. There are indications that this technology can be used in the food industry, alone or associated with chemical sanitizers. In this paper, we discuss the principles, mechanisms and effects of ultrasound on fruits and vegetables as a sanitization technology.
Full article at:
Title: Decontamination by ultrasound application in fresh fruits and vegetables
Source: Food Control. Volume 45, November 2014, Pages 36 – 50
Authors: Jackline Freitas Brilhante de São José, Nélio José de Andrade, Afonso Mota Ramos, Maria Cristina Dantas Vanetti, Paulo César Stringheta and José Benício Paes Chaves
Document Type: Research Article
Bubbles image by Ilena Gecan 2007 (under creative commons licence)

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Processing and storage of celery

An article published in the most recent issue of the Journal of Food Protection explains ‘mitigation strategies during dicing and proper refrigeration are essential to minimizing potential health risks associated with diced celery.’ The abstract reproduced below:
The transfer of Listeria monocytogenes to previously uncontaminated product during mechanical dicing of celery and its growth during storage at various temperatures were evaluated. In each of three trials, 275 g of retail celery stalks was immersed in an aqueous five-strain L. monocytogenes cocktail to obtain an average of 5.6 log CFU/g and then was diced using a hand-operated dicer, followed by sequential dicing of 15 identical 250-g batches of uninoculated celery using the same dicer. Each batch of diced celery was examined for numbers of Listeria initially and after 3 and 7 days of storage at 4, 7, and 10°C. Additionally, the percentage by weight of inoculated product transferred to each of 15 batches of uninoculated celery was determined using inoculated red stems of Swiss chard as a surrogate. Listeria transfer to diced celery was also assessed after removing the Swiss chard. L. monocytogenes transferred from the initial batch of inoculated celery to all 15 batches of uninoculated celery during dicing, with populations decreasing from 5.2 to 2.0 log CFU/g on the day of processing. At 10°C, Listeria reached an average population of 3.4 log CFU/g in all batches of uninoculated celery. Fewer batches of celery showed significant growth during storage at 4 and 7°C (P < 0.05). Swiss chard pieces were recovered from all 15 batches of celery, with similar amounts seen in batches 2 to 15 (P > 0.05). L. monocytogenes was also recovered from each batch of uninoculated celery after the removal of Swiss chard, with populations decreasing from 4.7 to 1.7 log CFU/g. Storing the diced celery at 10°C yielded a L. monocytogenes generation time of 0.87 days, with no significant growth observed during storage at 4 or 7°C. Consequently, mitigation strategies during dicing and proper refrigeration are essential to minimizing potential health risks associated with diced celery.
Full article at:
Title: Listeria monocytogenes transfer during mechanical dicing of celery and growth during subsequent storage
Source: Journal of Food Protection, Number 5, May 2014, pp. 696-863 , pp. 765-771(7)
Authors: Kaminski, Chelsea N; Davidson, Gordon R; Ryser, Elliot T
Document Type: Research Article

Celery image by J M Rosenfeld 2008 (under creative commons licence)

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Grants awarded to further collaboration with China

Four grants have been awarded under the New Zealand – China Food Safety & Security Roadmap to further develop scientific collaborations with China.
These include two travel grants and two workshop grants, and are expected to grow durable scientific collaborations between New Zealand and China, focused on the areas of food safety and security.
The Roadmap Advisory Committee has allocated $5,000 travel grants to Garry Hill and Yinqiu Wu from Plant & Food Research; and $20,000 workshop grants to Associate Professor Ravi Gooneratne’s team from Lincoln University and Associate Professor Yacine Hemar from the University of Auckland.
The five-year Roadmap operates under the framework of the China – New Zealand Strategic Research Alliance (SRA) established in 2010, and aims to create research opportunities, conduct research and deploy science outcomes into the marketplace. The Roadmap identified three areas of priority areas of cooperation – Food Safety and Security; Water Research; and Non-communicable Diseases. Plant & Food Research was chosen as the coordinating organisation for work in the Food Safety and Security priority area, and manages the grants on behalf of MBIE and their International Relationships Fund.

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Dr Robyn McConchie’s Report of Day 2 at CPS Research Symposium, 27th June 2013

The CPS at the University of Davis has been very supportive of the initiatives in Australia to establish an affiliated Fresh Produce Safety Centre. Over the past year they have very generously shared their research outcomes, they have given presentations to our industry, and this year invited Australian researchers to apply for research grants to work collaboratively with US scientists on issues important for the Australian fruit and vegetable industry.
As part of the ongoing collaboration Dr Robyn McConchie from the University of Sydney was invited to take part in a panel session at the recent 2013 CPS Research Symposium held at Wegman’s Conference Centre in Rochester, NY State. Due to the increasing awareness and interest from the US industry, the Research Symposium was held over 2 days. To view a summary of Day 1 on Listeria and Composts please click here.
Click here to view the outcomes of projects from the second day on “Water Quality for Irrigation and Postharvest Practices”, “Pathogen transference: Pre-harvest, harvest and Packaging.” And “Hot Topics.”

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New Research in Food safety at the 13th ASEAN Food Conference, Singapore 2013

The biennial ASEAN Food Conference is the leading forum for the food industry and research community in the region. The theme of the 13th ASEAN Food Conference held on the 9th-11th September 2013 in Singapore was “Meeting Future Food Demands: Security and Sustainability”.
Issues of malnutrition, undernutrition, and sustainable production were certainly important topics. However the themes were interpreted quite broadly to encompass, for example, how improvement in nutritional quality and food safety could benefit consumer health and community livelihoods, and help to address the alarming worldwide escalation in diet-related and lifestyle diseases. Sustainability was discussed less in terms of environmental impact, and more in terms of innovations in food processing, quality and safety to sustain long-term food industries.
The program included sessions on: managing innovation, nutrition & health, food chemistry & biochemistry, sensory science & consumer studies, food microbiology, food engineering, food processing, food product development, protein and weight management, food safety, food science and technology education, functional foods, nanotechnology of food, food analysis and quality assurance, and management of allergens in the food chain. The full program is available online, click here. 

The conference was about food generally, but some interesting topics relevant to produce safety included:

Development of a fermentation process to produce a natural preservative called phenyllactic acid (PLA) from Lactobacillus plantarum bacteria. The PLA was shown to have antimicrobial activity against a variety of pathogens and extended the shelf-life of fresh-cut pineapple and bottled pineapple juice (Bui Kim Thuy, Nguyen Duy Lam, and Nguyen Thi Hoai Tram).
Development of a Surface Plasmon Resonance biosensor and sensor chips with antibodies specific to Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. The biosensor is an experimental format that, if successful, would allow convenient simultaneous detection of target bacteria (Zhang Xiaoguang, Sachiko Tsuji, Ken-ichi Honjoh, and Takahisa Miyamoto).
Direct irradiation with LED has bactericidal effects on E. coli O157:H7, S. Typhimurium, and L. monocytogenes dependent on the pH of the medium and LED wavelength – blue is better than green! (Vinayak Ghate, Leong Ai Ling, and Yuk Hyun-Gyun).
Chitosan is a natural antimicrobial and antilisterial agent. Electron microscopy suggested that chitosan kills the bacteria by interfering with cell membrane permeability and causing leakage of cell contents (Juthamas Tantala, Titima Sukmark, Masubon Thongngam, Kanjana Thumanu, Pornchai Rachtanapun, Chitsiri Rachtanapun).
Establishment of a microbial risk assessment and food safety system for the Singapore retail sector by the National Environment Agency (NEA). The NEA is a government agency that has brought together regulatory activity and research to develop and deliver a risk-based inspection and education service. A unique feature of this relates to the cultural popularity of ready-to-eat food bought from stalls, which have special hygiene challenges (Ramona A  Gutierrez and Ng Lee Ching).
Site visit to the Agri-Food and Veterinary Authority of Singapore, which is the national food safety agency. Singapore imports 90% of its food from all over the world and has extremely well-resourced labs to test for chemical contaminants, additives and preservatives, drug residues, pesticide residues, food pathogens, foodborne parasites, physical quality, GMO, and other toxins. It also provides export certification, accreditation of food businesses, and food safety education; implements labelling and advertisement regulations and food recalls; and has a variety of roles relating to the animals and pet sector.

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