Category Archives: Research

Research into Toxoplasma gondii

Posted on December 24, 2012 by | 1 comment

Science DailyToxoplasma

Toxoplasma gondii is a parasite that commonly infects cats but is also carried by other warm-blooded animals, including humans. Up to a third of the UK population are chronically infected with the parasite. In most cases the acute infection causes only flu-like symptoms. However, women who become infected during pregnancy can pass the parasite to their unborn child which can result in serious health problems for the baby such as blindness and brain damage. People who have compromised immunity, such as individuals infected with HIV, are also at risk of serious complication due to reactivation of dormant cysts found in the brain.

Studies in the USA and UK state that up to 50% of infections can come from food.

Current thinking on how the Toxoplasma gondii parasite invades its host is incorrect, according to a study published today in Nature Methods describing a new technique to knock out genes. The findings could have implications for other parasites from the same family, including malaria, and suggest that drugs that are currently being developed to block this invasion pathway may be unsuccessful.

1 Comment

Posted in Food Hygiene, Food Safety, Food Testing, Microbiology, Parasite, Research, Toxoplasmosis

USA – Foodborne Illness Outbreaks Database 1984 – 2012

Posted on December 24, 2012 by | Leave a comment

Marler Clark

Welcome to outbreakdatabase.com, a searchable database of illness outbreaks caused by one or more of the following

  1. consumption of contaminated foods or beverages,
  2. exposure to animals,
  3. exposure to contaminated recreational water,
  4. person-to-person contact with someone whose illness initiated from animal exposure or consumption of contaminated foods and beverages.

The database describes outbreaks occurring since 1984.

The Centers for Disease Control and Prevention (CDC) defines an outbreak as “two or more ill persons linked to a common source” and this serves as the basis of outbreakdatabase.com. To be included in outbreakdatabase.com, the outbreak must have supporting documentation from public health agencies, journal articles, media reports, etc. Names of stores, brands, restaurants, or other sources are listed if they have been publicly identified previously.

The database is a work in progress. It will continually be updated and revised. Significant effort has been made to ensure the data are accurate. We welcome contributions, corrections, comments, etc. Please use the contact form for comments.

 

Leave a comment

Posted in Bacteria, FDA, Food Hygiene, Food Illness, Food Inspections, Food Poisoning, Food Safety, Food Safety Alert, Food Spoilage, Food Technology, Food Testing, Foodborne Illness, Hygiene, Illness, Methods, Microbiology, outbreak, Pathogen, Recall, Research

Tagged , ,

Canada Research – Peracetic Acid for Fresh Produce

Posted on December 24, 2012 by | Leave a comment

The Grower

Up to 10,000 pounds of spinach are washed and packaged every day in iVeg Pak’s Toronto, Ontario plant. No matter where the spinach originates – Mexico, Texas, New Jersey or Ontario – the end product goes into a Pop-i package. That brand must be protected, not only for the Carnevale family owners but for the entire food chain.

To meet those standards, Taylor McCarthy’s full-time job is quality assurance, taking water samples every hour and making sure that the spinach is in the peracetic acid bath for a minimum of 45 seconds before proceeding to a drum dryer.

“This sanitizer has proven to be very effective,” says McCarthy. “We are an industry leader in using this product instead of chlorine. It’s not as corrosive on the stainless steel equipment.”

Leave a comment

Posted in Bacteria, Food Hygiene, Food Poisoning, Food Safety, Methods, Microbiology, Research

Tagged ,

USA – Research -STEC Sampling and Listeria Outbreaks 1998-2008

Posted on December 20, 2012 by | Leave a comment

FSIS Notice

 This notice provides new instructions to inspection program personnel (IPP) for verifying and documenting the sample source (beef, veal, or mixed) in the Public Health Information System (PHIS) when collecting raw beef samples under FSIS’s verification testing programs for Shiga toxin-producing Escherichia coli (STEC).

CDC

Listeria monocytogenes, a bacterial foodborne pathogen, can cause meningitis, bacteremia, and complications during pregnancy. This report summarizes listeriosis outbreaks reported to the Foodborne Disease Outbreak Surveillance System of the Centers for Disease Control and Prevention during 1998–2008. The study period includes the advent of PulseNet (a national molecular subtyping network for outbreak detection) in 1998 and the Listeria Initiative (enhanced surveillance for outbreak investigation) in 2004. Twenty-four confirmed listeriosis outbreaks were reported during 1998–2008, resulting in 359 illnesses, 215 hospitalizations, and 38 deaths. Outbreaks earlier in the study period were generally larger and longer. Serotype 4b caused the largest number of outbreaks and outbreak-associated cases. Ready-to-eat meats caused more early outbreaks, and novel vehicles (i.e., sprouts, taco/nacho salad) were associated with outbreaks later in the study period. These changes may reflect the effect of PulseNet and the Listeria Initiative and regulatory initiatives designed to prevent contamination in ready-to-eat meat and poultry products.

Leave a comment

Posted in Bacteria, E.coli O104, E.coli O145, E.coli O157, E.coli O26, EHEC, Food Hygiene, Food Safety, Food Testing, Listeria, Listeria monocytogenes, Methods, Microbiology, Pathogen, Research, STEC

Tagged , ,

HPA – Scotland Cryptosporidum Increase 2012

Posted on December 19, 2012 by | Leave a comment

HPA Scotland763px-Cryptosporidium_parvum_01

By the end of the first 50 weeks of 2012, 684 cases of cryptosporidiosis had been reported to Health Protection Scotland. This was an increase of 256 (60%) over the same period in 2011.

In weeks 41-44 of 2012, 128 cases were reported. This was an increase of 84 (191%) over the same period in 2011. In weeks 45-48 of 2012, 74 cases were reported, an increase of 38 (106%) over the same period in 2011. However, in the first two weeks of the current period (weeks 49-52) of 2012, only 17 cases have been reported. In weeks 49-52 of 2011, a total of 39 cases were reported so the figure for weeks 49-52 of 2012, thus far, is unremarkable.

 

Leave a comment

Posted in Cryptosporidium, Food Standards Agency, HPA, Microbiology, Pathogen, Research

Tagged , ,

Research – Listeria Effect of Reduced Salt and Organinc Acids and Salt Derivatives

Posted on December 18, 2012 by | Leave a comment

Wiley Online Library

Abstract:  Reducing sodium in food could have an effect on food safety. The objective was to determine differences in growth of Listeria monocytogenes in meat and poultry systems with salt substitutes. For phase 1, fresh ground beef, pork, and turkey with NaCl, KCl, CaCl2, MgCl2, sea salt, or replacement salt added at 2.0% were inoculated with L. monocytogenes to determine growth/survival during 5 d at 4 °C to simulate a pre-blend process. L. monocytogenes populations significantly decreased (0.41 log CFU/g) during the storage time in beef, but no differences (P > 0.05) were observed over time in pork or turkey. Salt type did not affect (P > 0.05) L. monocytogenes populations during pre-blend storage. MgCl2 and NaCl allowed significant growth of aerobic populations during storage. For phase 2, emulsified beef and pork products were processed with 2% NaCl, KCl, sea salt, or a NaCl/KCl blend and post-process surface-inoculated with L. monocytogenes to determine growth/survival at 4 °C for 28 d. Pork products showed significantly greater L. monocytogenes population growth at all sampling times (0, 7, 14, 21, and 28 d) than beef products, but salt type had no effect on L. monocytogenes populations with sampling times pooled for data analysis. Although salt types had no impact on L. monocytogenes populations in preblend and emulsified meat products, pork and turkey preblends and emulsified pork had greater L. monocytogenes populations compared with beef products. These studies demonstrate that sodium may not affect the safety of preblends and emulsified meat and poultry products.

Practical Application:  odium reduction in food is an important topic because of sodium’s unfavorable health effects. This research shows that reducing sodium in pre-blends and emulsified meat and poultry products would have no effect on Listeria monocytogenes populations, but replacement of NaCl with MgCl2 may affect growth of aerobic populations.

Mary Ann Liebert

Abstract

This article reports on the antilisterial properties of selected organic acids and salt derivatives in order to suggest possible alternatives in food preservation and pathogen control in the poultry meat processing industry. The susceptibility of two Listeria monocytogenes isolates was assessed against five organic acids (lactic, acetic, malic, citric, and propionic) and two acid-salt derivatives (sorbic acid [potassium salt] and benzoic acid [sodium salt]) across a series of pH environments. Minimum inhibitory concentrations (MICs) of the acids were tested against the two strains by means of an agar-dilution method. In general, strain CC60 was found to be more resistant than strain CC77 to both organic acids and salts. At pH values of 7 and above, high MIC levels (low susceptibility) were noted for potassium sorbate, sodium benzoate, and lactic acids, whereas susceptibility at lower pH increased reaching pH5 where the isolates were susceptible to all the organic acids tested. A small increase in pH notably reduced antimicrobial activity against the organisms. At pH 7, the isolates just about lost susceptibility to benzoic, lactic, malic, and sorbic acids. Although the activity of the majority of acids was linked to pH, some acids were not as closely related (e.g., potassium sorbate, sodium benzoate, and citric acid), and this suggests that the type of organic acids plays a role in inhibition. The relatively high MICs reported for compounds that are conventionally used as preservatives against Listeria spp. raise concern. The results furthermore suggest that the type of organic acid used to set pH, and not only pH alone, plays a role in determining inhibition. It was confirmed that a “one size fits all” approach to preservation is not always effective. Furthermore, the need for microbiological data to the subspecies level to inform the selection of preservatives was highlighted.

Leave a comment

Posted in Bacteria, Food Inspections, Food Safety, Food Technology, Food Testing, Listeria, Listeria monocytogenes, Listeria welshimeri, Microbiology, Pathogen, Research

Research – Cold Atmosphric Gas Plasma – Salmonella. Radio Frequency Heating E.coli O157. Simultaneous physicochemical stresses – Salmonella

Posted on December 17, 2012 by | Leave a comment

Science Direct

Cold atmospheric gas plasma treatment (CAP) is an alternative approach for the decontamination of fresh and minimally processed food. In this study, the effects of growth phase, growth temperature and chemical treatment regime on the inactivation of Salmonella enterica serovar Typhimurium (S. Typhimurium) by Nitrogen CAP were examined. Furthermore, the efficacy of CAP treatment for decontaminating lettuce and strawberry surfaces and potato tissue inoculated with S. Typhimurium was evaluated. It was found that the rate of inactivation of S. Typhimurium was independent of the growth phase, growth temperature and chemical treatment regime. Under optimal conditions, a 2 min treatment resulted in a 2.71 log-reduction of S. Typhimurium viability on membrane filters whereas a 15 min treatment was necessary to achieve 2.72, 1.76 and 0.94 log-reductions of viability on lettuce, strawberry and potato, respectively. We suggest that the differing efficiency of CAP treatment on the inactivation of S. Typhimurium on these different types of fresh foods is a consequence of their surface features. Scanning electron microscopy of the surface structures of contaminated samples of lettuce, strawberry and potato revealed topographical features whereby S. Typhimurium cells could be protected from the active species generated by plasma.

Science Direct

A multistate outbreak of Salmonella enterica serovar Typhimurium recently occurred in the USA, which was traced back to various food products made with contaminated peanut butter. This study was conducted to investigate the efficacy of radio-frequency (RF) heating to inactivate S. Typhimurium and Escherichia coli O157:H7 in peanut butter cracker sandwiches using creamy and chunky commercial peanut butter and to determine the effect on quality by measuring color changes and sensory evaluation. Samples were treated for a maximum time of 90 s in a 27.12 MHz RF heating system. Samples were prepared in the form of peanut butter cracker sandwiches and placed in the middle of two parallel-plate electrodes. After 90 s of RF treatment, the log reductions of S. Typhimurium and E. coli O157:H7 were 4.29 and 4.39 log CFU/g, respectively, in creamy peanut butter. RF treatment of chunky peanut butter for 90 s also significantly (P < 0.05) reduced levels of S. Typhimurium and E. coli O157:H7 by 4.55 log CFU/g and 5.32 log CFU/g. Color values and sensory characteristics of the RF treated peanut butter and crackers were not significantly (P > 0.05) different from the control. These results suggest that RF heating can be applied to control pathogens in peanut butter products without affecting quality.

Science Direct

The effects of prior simultaneous pH (3.0–8.0), water activity, aw (0.93–0.99) and temperature (3.0–62.0 °C) stresses on injury and subsequent resistance of Salmonella Enteritidis to acid (pH 3.78, 25 °C) and heating (pH 3.78, 55 °C) in apple juice were determined. Injury rates were significantly (P < 0.05) influenced by the linear effects of aw and temperature. Exposure to combinations (pH 4.0, aw 0.98, 15 °C) and (pH 5.5, aw 0.99, 32.5 °C) resulted in acid adaptation. Only the linear influence of prior aw stress significantly affected the subsequent acid resistance. Heat resistance was greatest after previous exposure to pH, aw and temperature ranges of 4.0–5.5, 0.96–0.98, and 15–50 °C, respectively. None of the stress factors significantly influenced subsequent heat resistance. These results provide a more realistic simulation of the effects of environmental stress factors on the behavior of S. Enteritidis in food and food processing ecologies; and contribute in further understanding the behavior of the pathogen for the improvement of evaluation and control of safety of apple juice and similar products.

 

Leave a comment

Posted in Bacteria, E.coli O157, Microbiology, Research, Salmonella

Tagged , ,

Research – Grape Seed Extract Effect on Virus and E.coli on Fresh Cut Lettuce

Posted on December 17, 2012 by | Leave a comment

Science Direct

Grape seed extract (GSE) is reported to have antibacterial properties with few current studies on antiviral activity. Recently, we reported the effects of GSE against foodborne viral surrogates in vitro. This study evaluated the application of GSE (commercial Gravinol-S) against hepatitis A virus (HAV) and human norovirus surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1), on model produce. Washed and air-dried lettuce (3 × 3 cm2) and jalapeno peppers (25–30 g) were inoculated with FCV-F9, MNV-1, or HAV at high (∼7 log10 PFU/ml) or low (∼5 log10 PFU/ml) titers, and treated with 0.25, 0.5, 1 mg/ml GSE or water for 30 s to 5 min. Treatments were stopped/diluted with cell-culture media containing 10% heat-inactivated fetal bovine serum and evaluated using plaque assays. At high titers, FCV-F9 was reduced by 2.33, 2.58, and 2.71 log10 PFU on lettuce; and 2.20, 2.74, and 3.05 log10 PFU on peppers after 1 min using 0.25, 0.50, and 1 mg/ml GSE, respectively. Low FCV-F9 titers could not be detected after 1 min at all three GSE concentrations. Low titer MNV-1 was reduced by 0.2–0.3 log10 PFU on lettuce and 0.8 log10 PFU on peppers, without reduction of high titer. GSE at 0.25–1 mg/ml after 1 min caused 0.7–1.1 and 1–1.3 log10 PFU reduction for high and low HAV titers, respectively on both commodities. Instrumental color analysis showed no significant differences between treated and untreated produce. GSE shows potential for foodborne viral reduction on produce as part of hurdle technologies.

Direct Science

Fresh-cut iceberg lettuce inoculated with Escherichia coli O157:H7 was submitted to chlorine washing (150 mg/mL) and modified atmosphere packaging on laboratory scale. Populations of E. coli O157:H7 were assessed in fresh-cut lettuce stored at 4, 8, 13 and 16 °C using 6–8 replicates in each analysis point in order to capture experimental variability. The pathogen was able to grow at temperatures ≥8 °C, although at low temperatures, growth data presented a high variability between replicates. Indeed, at 8 °C after 15 days, some replicates did not show growth while other replicates did present an increase. A growth primary model was fitted to the raw growth data to estimate lag time and maximum growth rate. The prediction and confidence bands for the fitted growth models were estimated based on Monte-Carlo method. The estimated maximum growth rates (log cfu/day) corresponded to 0.14 (95% CI: 0.06–0.31), 0.55 (95% CI: 0.17–1.20) and 1.43 (95% CI: 0.82–2.15) for 8, 13 and 16 °C, respectively. A square-root secondary model was satisfactorily derived from the estimated growth rates (R2 > 0.80; Bf = 0.97; Af = 1.46). Predictive models and data obtained in this study are intended to improve quantitative risk assessment studies for E. coli O157:H7 in leafy green products.

 

Leave a comment

Posted in Bacteria, E.coli O157, Food Hygiene, Food Illness, Food Inspections, Food Poisoning, Food Safety, Food Technology, Food Testing, Food Virus, Hepatitis A, Hygiene, Illness, Methods, Microbiology, Norovirus, Pathogen, Research, STEC

Tagged , , ,

Research – Norovirus v Dishwashers

Posted on December 12, 2012 by | Leave a comment

Food Poisoning Bulletin

What do norovirus and baked-on lasagna have in common? Both can survive the dishwasher.

Researchers at Ohio State University have made a discovery that may help to explain why restaurants have a hard time controlling the spread of norovirus, the leading cause of food poisoning worldwide. About half of all foodborne illness outbreaks in the US are caused by norovirus, most of them, about 80 percent, happen between November and April, according to the Centers for Disease Control and Prevention (CDC).

Leave a comment

Posted in CDC, Eurofins Laboratories, Food Hygiene, Food Illness, Food Inspections, Food Poisoning, Food Safety, Food Testing, Food Virus, Hygiene, Illness, Microbiology, Norovirus, Pathogen, Research

Tagged , ,

Research – E.coli O157 Testing in Water

Posted on December 10, 2012 by | Leave a comment

Science Direct

The performances of three chromogenic agars were evaluated for the recovery of Escherichia coli O157:H7 from spiked de-chlorinated tap, ground and surface water, and treated drinking water samples. The chromogenic agars: ChromAgar O157 (CHROM), Rainbow Agar O157 (RB) and HiCrome EC O157 (HC) were compared to cefixime-tellurite Sorbitol MacConkey (CT-SMAC), commonly used for the isolation of E. coli O157:H7. Confirmation of suspect E. coli O157:H7 colonies were performed by colony real-time PCR (C-RTi-PCR) based on the presence of Shiga-toxin genes (stx1 and stx2). Recovery of inoculated E. coli O157:H7 from de-chlorinated tap water indicated that RB and CHROM agars demonstrated improved recovery when compared to HC or CT-SMAC. There was a significant drop in recovery on all agars tested after 120 hours (day 5). Twenty de-chlorinated tap and/or treated drinking water samples were inoculated with a pure culture of E. coli O157:H7 (ATCC 43894), and a mixed culture of E. coli O157:H7 (ATCC 43894), E. coli strain K-12, and Enterococcus faecalis (ATCC 063589). After a 48 hour holding time, the recovery using CHROM (99 %) and HC (12 %) from samples contaminated with the pure culture were found to be significantly different (p < 0.05). Recovery results using CHROM (39 %) and CT-SMAC (32 %) from samples contaminated with the mixed culture after 48 hour holding time were not significantly different (p > 0.05). Analysis by C-RTi-PCR of forty five environmental water samples (surface, sewage, and final effluents) which were negative for E. coli O157:H7 showed an incidence of false suspect positive colonies of 38 % (CHROM), 53 % (RB), 58 % (HC), and 91 % (CT-SMAC). Further analysis of eight of the environmental samples inoculated with E. coli (ATCC 43894) showed 100% recovery when utilizing CHROM, 50% when using RB and 40 % when using HC. In addition, the C-RTi-PCR positive confirmation rate was 100% for CHROM and HC and 65% for RB. CHROM demonstrated improved recovery of E. coli O157:H7 over RB, HC, and CT-SMAC in terms of sensitivity and specificity.

Leave a comment

Posted in E.coli, E.coli O157, Methods, Microbiology, Pathogen, Research

Tagged