Towards biotracing in food chains

Hoorfar, Jeffrey; Wagner, Martin; Jordan, Kieran; Bouquin, Solveig Lind; Skiby, Jeffrey Edward

doi:10.1016/j.ijfoodmicro.2010.04.028

Cited by 11 publications

(5 citation statements)

References 10 publications

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“…The main purpose of this part of the overall study was to evaluate the quality of milk being produced on farms in South Africa in terms of AFM1 contamination in order that biotracer (Hoorfar et al 2011) work on the mycotoxin could be carried out and to develop suitable methods of analysis. Without the presence of any mycotoxin any such study would be at best hypothetical.…”

Section: Resultsmentioning

confidence: 99%

Mycotoxins in South African foods: a case study on aflatoxin M1 in milk

et al. 2011

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The contamination of cow's milk at the farm level with aflatoxin M1 was investigated in South Africa. Samples of feeds, forage, maize and milk were taken at nine dairy farms, and at the same time samples of the processed milk (retail milk) were collected from the respective dairies to which the farms delivered their milk. The feeds were analysed for aflatoxin B1 and the milk samples for aflatoxin M1 using high performance liquid chromatography (HPLC) and fluorescence detection. All milk samples from the dairy farms were positive for aflatoxin M1, ranging from 0.02 μg/l to 1.5 μg/l. Retail milk was also frequently contaminated with AFM1, at levels of 0.01-3.1 μg/l. High AFB1 levels in feed materials on the farms supplying the raw milk indicate that various sources account for this contamination frequency in milk.

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Section: Resultsmentioning

confidence: 99%

Mycotoxins in South African foods: a case study on aflatoxin M1 in milk

et al. 2011

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“…Thus tracing the origin of accidental or deliberate microbial contamination of feed and food is essential to establish corrective actions that prevent this contamination [30]. Hysteretic responses to environmental conditions and stresses associated with food production and process could be investigated to infer the time and point of contamination throughout the food chain.…”

Section: Discussionmentioning

confidence: 99%

The Transcriptional Heat Shock Response of Salmonella Typhimurium Shows Hysteresis and Heated Cells Show Increased Resistance to Heat and Acid Stress

Hansen

Muñoz-Cuevas

et al. 2012

PLoS ONE

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We investigated if the transcriptional response of Salmonella Typhimurium to temperature and acid variations was hysteretic, i.e. whether the transcriptional regulation caused by environmental stimuli showed memory and remained after the stimuli ceased. The transcriptional activity of non-replicating stationary phase cells of S. Typhimurium caused by the exposure to 45°C and to pH 5 for 30 min was monitored by microarray hybridizations at the end of the treatment period as well as immediately and 30 minutes after conditions were set back to their initial values, 25°C and pH 7. One hundred and two out of 120 up-regulated genes during the heat shock remained up-regulated 30 minutes after the temperature was set back to 25°C, while only 86 out of 293 down regulated genes remained down regulated 30 minutes after the heat shock ceased. Thus, the majority of the induced genes exhibited hysteresis, i.e., they remained up-regulated after the environmental stress ceased. At 25°C the transcriptional regulation of genes encoding for heat shock proteins was determined by the previous environment. Gene networks constructed with up-regulated genes were significantly more modular than those of down-regulated genes, implying that down-regulation was significantly less synchronized than up-regulation. The hysteretic transcriptional response to heat shock was accompanied by higher resistance to inactivation at 50°C as well as cross-resistance to inactivation at pH 3; however, growth rates and lag times at 43°C and at pH 4.5 were not affected. The exposure to pH 5 only caused up-regulation of 12 genes and this response was neither hysteretic nor accompanied of increased resistance to inactivation conditions. Cellular memory at the transcriptional level may represent a mechanism of adaptation to the environment and a deterministic source of variability in gene regulation.

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“…In the future, the source identification may be modeled in Bayesian Belief Networks to point to the source. This new concept, referred to as biotracing ( Hoorfar et al., 2010 ), can combine laboratory results obtained from detection of pathogen‐specific genes, with information collected during the entire food process to make sound decisions about possible product recalls (food ‘forensics’) or determine the source of possible contamination (Barker et al., 2009). The concept is the foundation of the European Integrated Project BIOTRACER (http://www.biotracer.org; Hoorfar et al., 2010 ).…”

Section: Future Trendsmentioning

confidence: 99%

Rapid detection, characterization, and enumeration of foodborne pathogens

Hoorfar

2011

APMIS

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As food safety management further develops, microbiological testing will continue to play an important role in assessing whether Food Safety Objectives are achieved. However, traditional microbiological culture-based methods are limited, particularly in their ability to provide timely data. The present review discusses the reasons for the increasing interest in rapid methods, current developments in the field, the research needs, and the future trends. The advent of biotechnology has introduced new technologies that led to the emergence of rapid diagnostic methods and altered food testing practices. Rapid methods are comprised of many different detection technologies, including specialized enzyme substrates, antibodies and DNA, ranging from simple differential plating media to the use of sophisticated instruments. The use of non-invasive sampling techniques for live animals especially came into focus with the 1990s outbreak of bovine spongiform encephalopathy that was linked to the human outbreak of Creutzfeldt Jakob's Disease. Serology is still an important tool in preventing foodborne pathogens to enter the human food supply through meat and milk from animals. One of the primary uses of rapid methods is for fast screening of large number of samples, where most of them are expected to be test-negative, leading to faster product release for sale. This has been the main strength of rapid methods such as real-time Polymerase Chain Reaction (PCR). Enrichment PCR, where a primary culture broth is tested in PCR, is the most common approach in rapid testing. Recent reports show that it is possible both to enrich a sample and enumerate by pathogen-specific real-time PCR, if the enrichment time is short. This can be especially useful in situations where food producers ask for the level of pathogen in a contaminated product. Another key issue is automation, where the key drivers are miniaturization and multiple testing, which mean that not only one instrument is flexible enough to test for many pathogens but also many pathogens can be detected with one test. The review is mainly based on the author's scientific work that has contributed with the following new developments to this field: (i) serologic tests for large-scale screening, surveillance, or eradication programs, (ii) same-day detection of Salmonella that otherwise was considered as difficult to achieve, (iii) pathogen enumeration following a short log-phase enrichment, (iv) detection of foodborne pathogens in air samples, and finally (v) biotracing of pathogens based on mathematical modeling, even in the absence of isolate. Rapid methods are discussed in a broad global health perspective, international food supply, and for improvement of quantitative microbial risk assessments. The need for quantitative sample preparation techniques, culture-independent, metagenomic-based detection, online monitoring, a global validation infrastructure has been emphasized. The cost and ease of use of rapid assays remain challenging obstacles to surmount.

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Towards biotracing in food chains

Cited by 11 publications

References 10 publications

Mycotoxins in South African foods: a case study on aflatoxin M1 in milk

Mycotoxins in South African foods: a case study on aflatoxin M1 in milk

The Transcriptional Heat Shock Response of Salmonella Typhimurium Shows Hysteresis and Heated Cells Show Increased Resistance to Heat and Acid Stress

Rapid detection, characterization, and enumeration of foodborne pathogens

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