Welcome to the Microbiology Information

This must be pretty bad if there is a national recall of baby spinach in the USA. As for the supplier, it’s either they knew the laboratory results and ignored it or they just could not control the problem. Either way, it’s poor management and it affected 28 different brands.

Here what the FDA says in the press release:

FDA Warning on Serious Food borne E.coli O157:H7 Outbreak -”One Death and Multiple Hospitalizations in Several States

“The U.S. Food and Drug Administration (FDA) is issuing an alert to consumers about an outbreak of E. coli O157:H7 in multiple states that may be associated with the consumption of produce. To date, preliminary epidemiological evidence suggests that bagged fresh spinach may be a possible cause of this outbreak.

At this time, the investigation is ongoing and states that have reported illnesses to date include: Connecticut, Idaho, Indiana, Michigan, New Mexico, Oregon, Utah and Wisconsin.”

Although there are many different brands implicated, here’s what one of the 28 brands (Dole Foods) affected says:

“Dole Foods Inc. announced that it supports the voluntary recall issued today by Natural Selection Foods LLC of packaged fresh spinach that Natural Selection Foods produced and packaged with Best-If-Used-By dates from August 17 through October 1, 2006. These packages were sold fewer than 28 different brand names, one of which was DOLE®. Natural Selection Foods produced and packaged all spinach items under the DOLE label (with the names “Spinach,” “Baby Spinach” and “Spring Mix”). Dole has no ownership or other economic interest in Natural Selection Foods.

Did you know that among the E. coli human pathogens, Verotoxin (Shiga-like toxin) forming strains (VTEC) have gained in importance in recent years. The group of enterohaemorrhagic E. coli (EHEC) with its highly pathogenic serovars 0157:H7, 026, 0103, 0111, 0145, and other strains are of particular concern.

Verotoxins can be classified into two main categories Verotoxin 1 (VT1, SLT1, Stx1) and Verotoxin 2 (VT2, SLT2, Stx2). EHEC strains may produce either VT1 or VT2 only or both VT1 and VT2 simultaneously. EHEC are capable of initiating life threatening illnesses, particularly in those with immune deficiency, young children and the elderly.

Detection of verotoxin is the easist way in which you can determine if the E.coli of interest is a pathogen of real concern.

E.coli is common everywhere with the main sources of infection being contaminated, raw or insufficiently heated foods of animal origin, e.g. meat and dairy products.

The reservoir for EHEC is the feces of cattle, sheep and goats. These microorganisms can enter food during the processing of meat and dairy products if hygienic conditions are inadequate. The drastic increase in the incidence of food infection caused by E. coli 0157 demands reliable and rapid methods of detection. In addition to traditional culture methods, immunological techniques are becoming more useful due to their improved specificity and sensitivity.

Duopath® Verotoxins is an immunological screening test based on the immune flow principle. The Duopath® Verotoxins GLISA test is an immunochromatographic rapid test intended to be used in food-analysing laboratories for the qualitative detection of Verotoxins (Shiga-like toxins) 1 and 2 from Verotoxinogenic E. coli (including E. coli O157:H7) isolated from food enrichments using FDA, USDA or other food enrichment methods.

This test has been validated and received AOAC approval for detection of Verotoxins 1 and 2 from isolated Verotoxin-producing E.coli (including E. coli O157:H7). Duopath® Verotoxin is also intended to be used in clinical laboratories for the qualitative identification of Verotoxins 1 and 2 (Shiga-like toxins 1 and 2) produced by E. coli isolated in cultures derived from clinical stool specimens. The identification aids in the diagnosis of diseases caused by enterohemorrhagic E. coli infections.

Did you know E. coli are divided into four different subgroups. These are A, B1, B2 and D based on a
range of factors including genetics, phenotype and ecology. Group A and B1 strains occur in all vertebrate hosts and in water; Group B2 strains are found in warm-blooded vertebrates with hindgut fermentation; Group D strains are found in warm-blooded vertebrates.

In general, A and B1 strains appear to be generalists, acquired by their hosts from the environment, and which colonise
well but persist poorly. B2 and D strains, which encode the most virulence factors, appear to be acquired from other host animals, colonise poorly but persist well.

The distribution of the subgroups in human populations varies in different parts of the world. The prevalence of subgroups in humans may change with age in population and there appears to be a gender effect.

In water, B1 strains are by far the most dominant, with B2 and D strains rarely found. Interestingly, B1 strains have similar sugar utilisation patterns and optimal growth temperatures whether isolated from water or faeces, while A strains differ in both these characteristics depending on their origin. B1 strains appear to survive the transition to the aquatic environment best, with B2 and D strains surviving relatively poorly in water. Exposure to the aquatic environment appears to select for a subset of group A strains.

The presence of E. coli in ready-to-eat foods is undesirable because it indicates poor hygienic conditions which have lead to contamination or inadequate heat treatment.

Ideally E. coli should not be detected and as such a level of <3 cfu per gram (the limit of the Most Probable Number test) has been given as the satisfactory criteria by regulatory authority around the world in food for this organism. Levels exceeding 100 cfu per gram are unacceptable and indicate a level of contamination which may have introduced pathogens or that pathogens, if present in the food prior to processing, may have survived.

Coliforms and E. Coli No Synopsis Available

E. coli are bacteria that normally live in the intestines of humans and animals. Although most strains are harmless, several are known to produce toxins that can cause diarrhea. One particular E. coli strain called O157:H7 or VTEC 0157 can cause severe diarrhea and kidney damage.

This bacterium can infect anyone; however the very young and the elderly are more likely to develop serious complications. Infection occurs when contaminated food is consumed. The bacteria live in the intestines of some healthy cattle and contamination of the meat may occur in the slaughtering process. Deer meat such as venison may also be infected with the organism. Eating meat that is rare or inadequately cooked is the most common way of getting the infection. The same applies with fresh vegetables, unpasteurized fruit juices and raw milk, all of which have also caused outbreaks.

Poor food handling with raw food product such as raw meat juices can easily transfer this bacterium to cooked foods causing post process contamination. Person-to-person transmission, especially in child care settings, can occur if infected people do not wash their hands after using the toilet or diapering children (E.coli is common in feces). Drinking contaminated water and swimming in contaminated shallow lakes may also cause infection. Exposures have also occurred from farm animals, particularly calves and cows, and deer jerky which is uncooked dried meat.

Good hygiene is the key to ensuring safe food products, however if you want further information I recommend The Official Patient’s Sourcebook on E. Coli

Did you know that there are many anti-bacterial products such as wipes that claim to kill of 99.9% of microorganisms. Of course the common pathogens are usually killed such as salmonella and E.coli, but what about the resistant strains and the more resistant pathogens such as bacillus cereus and staphylococcus aureus that has slowly built up immunity to the chemicals overtime and are not killed. What about all the other 99.9% of different potential microroganisms that resides in different areas of the world. Most of these wipes usually have one mode of action to remove or reduce the microorganisms present. They do this by targeting different pathways to inactivate the microorganisms such as oxidating, deactivation of the protein, disruption of the cell wall and so forth. The only way to effectively reduce the micro-organisms is to use different types that has a different mode of action. Attack them on multiple fronts.

Here’s the solution, why not rotate the wipes that contains chemicals that has a different activity every week; that way you are sure to kill the strain that wasn’t removed by the previous one. For example Quaternary ammonium compound, Chloride, 70% alcohol, benzyl akonium chloride, iodine and so forth just to name a few. Make sure that the wipes you do purchase do contain chemicals that have a different mode of action.