Showing posts with label food infection. Show all posts
Showing posts with label food infection. Show all posts

Sunday, 10 February 2013

RAPID TESTS FOR FOOD INFECTION-WILL THEY EVER REPLACE CULTURE TESTS?

Food-borne infection episodes are becoming more and more conspicuous by their recurring occurrence in countries like the US and fast detection and identification of the contaminant is a high priority area of interest to the industry. Conventional culture tests take at least 24 hours though in many cases it may stretch to 3-5 days. As the volume of production is increasing day by day due to growing demand for processed foods, it is next to impossible for the industry to organize culture based diagnosis and this is pushing the scientific community to evolve quick tests as a part of the safety protocol for helping the industry. There are a few quick tests available now which can give results under an hour and these are being increasingly deployed in the industry. But there is no unanimity whether such quick tests can be solely depended upon and the conventional culture tests can be dispensed with totally. Here is a critique on this vital issue which needs to be resoled quickly for a universal regime acceptable o all the stake holders.  

"Tests for food-borne pathogens in which a culture is not grown in a lab may be necessary for produce companies, but they can't replace traditional culture tests, industry leaders and government officials say. Non-culture diagnostic tests have been around since the early 1980s, said David Gombas, senior vice president of food safety and technology for the Washington D.C.-based United Fresh Produce Association. But there has been a recent push, Gombas said, to use them to replace culture tests that the Centers for Disease Control and Prevention, the Food and Drug Administration and other agencies and organizations rely on to accurately diagnose cases of salmonella, E. coli and other food-borne illnesses. That trend was highlighted in a recent article in Scientific America magazine, which found that many clinics and state-run labs are turning to nonculture tests, which are faster than culture tests. They're faster, but are they better? "Right now, the answer is no," Gombas said. "CDC, FDA, and those in the produce industry I talk to — they want a live bug." A live bug is the result of growing a culture, which can take 18 to 24 hours in a lab, Gombas said. Some of the rapid non culture tests, by contrast, can be done in 20 minutes. For many fresh produce companies, like Earthbound Farm, San Juan Batista, Calif., rapid non culture tests are a necessity, said Will Daniels, Earthbound's senior vice president of operations and organic integrity. "Without them, we wouldn't be able to do what we do," Daniels said. "A culture is a three to five day process. We can't fit that into our system." Earthbound Farms tests every product it ships. If it relied on culture tests and had to wait three to five days to ship, it would need to have five to six days' worth of inventory on hand at any given time, Daniels said."

There is point in the argument of the industry that it cannot hold on to huge stocks of foods in their warehouses, waiting for the results of culture tests to arrive before releasing into the market and naturally inventory management can be a nightmare, especially for large manufacturers, affecting their economical viability. At the same time consumer safety is sacrosanct and cannot be compromised at any cost. Probably safety scientists may have to evolve some sort of empirical correlation between quick testing regime and frequency of culture testing to make sure that the system s absolutely reliable. It must be admitted that quick tests are possible only for known pathogens and as and when new bugs arrive, culture tests are inevitable to identify them. Considering the enormity of the problem, food industry should not rely entirely on modern quick tests and do way with conventional diagnostic tools!

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

Sunday, 19 August 2012

FOOD BORNE INFECTION-FIGHTING WITH LACTOBACTERIA

"Taking out thorn with thorn" is an old saying meaning that any treatment to succeed, its intensity has to be equally as strong as the cause of the ailment. This is an approach increasingly becoming a feasible proposition in treating some infections caused by pathogens in humans. Recent reports suggesting that one of the Lactobacillus species viz L.reuteri can be an effective antidote to neutralize the pathogens are encouraging and already there are many patents on the proprietary ownership of some of the strains foreseeing the commercial potential of these findings. L.reuteri is an ubiquitous microorganism residing in the guts of mammals and birds and it was only in 1980s its full identification was made. It is a major component of gut microorganisms and occur practically every where including milk and meat products. However in some persons these microbes were not found, reasons for which are not well understood. It is thanks to L reuteri that most human beings are able to shake off most of the minor gastrointestinal infections encountered in day to day life. More importantly L.reuteri can inhibit the growth of one of the scourges of modern food industry, Salmonella which is causing hundreds of food poisoning episodes world-wide. The antibiotic effect of this beneficial bug has been attributed to excretion of chemicals like 3-hydroxypropionaldehyde, its hydrate and the dimer, collectively called Reuterin.     

"Their results demonstrated that this beneficial or probiotic organism, which produces an antimicrobial substance known as reuterin, may protect intestinal epithelial cells from infection by the foodborne bacterial pathogen Salmonella. Cheryl Nickerson and her group at ASU's Biodesign Institute, in collaboration with an international team including Tom Van de Wiele and lead author Rosemarie De Weirdt at Ghent University, Belgium, conducted the study. It examines for the first time the effect of reuterin during the infection process of mammalian intestinal cells and suggests the efficacy of using probiotic bacteria or their derivatives in future therapies aimed at thwarting Salmonella infection. Intestinal infections by non-typhoidal Salmonella strains induce diarrhea and gastroenteritis, and remain a leading source of foodborne illness worldwide. Such infections are acutely unpleasant but self-limiting in healthy individuals. For those with compromised immunity however, they can be deadly and the alarming incidence of multi-drug resistant Salmonella strains has underlined the necessity of more effective therapeutics. The use of benign microorganisms offers a promising new approach to treating infection from pathogens like Salmonella and indeed, L. reuteri has been shown to help protect against gastrointestinal infection and reduce diarrhea in children. The origin of L. reuteri's protective role still remains unclear. While it has been speculated that reuterin acts by regulating immune responses or competing with Salmonella for key binding sites, the current study represents the first in vitro examination of host-pathogen interactions using human intestinal epithelium in the presence of reuterin-producing L reuteri."

The early stage immunity in newly born babies was thought to be due to presence of Lactobacillus bifidi present in breast milk but after the discovery of L.reuteri, there is a new thinking that this organism also must be contributing to the health of the baby. However one peculiar feature of production of Reuterin is that glycerol is a precursor from which the antibiotic brew is produced. Of course glycerol is a component of Tri Carboxylic Acid (TCA) cycle or Krebs cycle involved in energy metabolism in humans and therefore L.reuteri can always produce the antibiotic in the gut region to the extent required to counteract the undesirable action of unfriendly microorganisms. Another interesting benefit of L.reuteri is that it can effectively protect teeth from the decays caused by Streptococcus mutans, found in the oral cavity of many people. Therapeutic preparations of L.reuteri are now available for rehabilitating the heath of gut microbiome as well as to ensure good dental health. Sensing the business potential offered by this unique bug there are yogurt products being offered in the market fortified with L.reuteri, though no one is sure how far such products are superior to normally made yogurts.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com