Your all-time favourites

I have just reviewed the most common search terms resulting in visits to this blog.

By far the most common has been "Coliforms in food".  This has been a regular search since I started writing Safe Food in 2006, but has perhaps appeared more frequently since the Escherichia coli O104:H4 outbreak in Europe.

Coliforms are used as "indicator organisms" to show whether the food has been processed under hygienic conditions.  Presence of these bacteria mean that the food has potentially been contaminated with faecal material and hence faecal organisms, but to confirm this, we look for Escherichia coli presence in the food.

Surprisingly, the next most common search has been "Safety of Probiotics".  Probiotic bacteria are those that confer some benefit on the host.  Thus many foods, such as yoghurt, contain live bacteria that may colonise the gut of the consumer and confer some benefit.  These bacteria are often lactic acid bacteria.  Many claims have been made for the benefits of consumption, though there are some indications that administration to critically ill patients with acute pancreatitis may have deleterious effects.  There is also some evidence that administration to infants under 6 months of age may render them more prone to development of sensitivity to allergens.  For the majority of consumers, however, probiotics will not be hazardous and may be beneficial.

Do not confuse probiotics with "prebiotics".   These were so named by Marcel Roberfroid in 1995, who later wrote the definition: "A prebiotic is a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health."  A major class of prebiotic is soluble fibre.

Much lower down the list are "Listeria in vegetables" and "Safety of chicken".  There has been a small spike in Listeria searches, probably as a result of recent recalls and the cantaloupe outbreak in USA that has killed approximately 29 people.  The incidence of listeriosis is very low and victims are usually neonates, the elderly and those people with compromised immune systems, but this outbreak seems to have been particularly dangerous.  Chicken has made regular appearances in the news, either being a vehicle for Salmonella or Campylobacter.  The incidence of Campylobacter infections in New Zealand has dropped significantly since the introduction of more stringent controls and biosecurity systems.

One new search now appearing is a bit disturbing: "Will eating spoiled food make you sick?".  I have previously written on this after receiving a direct question from a reader.  Is the increased interest a result of hardship in the community, or merely a thirst for knowledge?  I hope it is the latter.

Dangerous probiotics? Probably not

Readers may have been concerned to hear last week of 24 unexplained deaths among patients with acute pancreatitis, who were being administered probiotics in a study conducted at the University Medical Centre in Utrecht. The deaths occurred between 2004 and 2007 and represented 16% of the 296 patients in the trial. Unfortunately, the original reports are in Dutch and it is difficult to glean the full facts, including the percentage of patients in the control group who died.

It appears that the patients all had serious acute pancreatitis – inflammation of the pancreas. This disease may have a number of causes, but alcohol abuse and gallstones account for 80-90% of cases. Scarring of the pancreas during an attack may lead to chronic disease that can become life threatening.

The research concerned the functioning of probiotic bacteria administered to reduce the effects of the pancreatitis. The investigation was conducted in fifteen hospitals under the guidance of UMC Utrecht. If I have interpreted the press reports correctly, an investigation of the deceased showed that no infection resulted from the administration of the probiotics. However, three factors appear to be involved: treatment with probiotics of patients having organ failure; treatment of patients in intensive care; treatment of patients being fed by probe directly into the digestive tract. The researchers have recommended that if a patient satisfies one or more of these criteria, they should not be administered probiotics. A similar trial in Czechia has been stopped.

It had been thought that the administration of probiotic bacteria would raise the patients’ resistance to detrimental bacteria colonizing the gut.

Not surprisingly, the main manufacturers of probiotic cultures have reacted strongly, stating that there is no evidence that feeding of probiotics has a deleterious effect on healthy individuals. They have also claimed that the bacteria in the study are different from those in their own products.

I’m sure we haven’t heard the last of this, but in the meantime I suggest that normal, healthy adults should continue eating their probiotic-containing yoghurt or drinking their daily dose of probiotic cultures. The benefits of probiotic bacteria have been known for many years and countless people have consumed them without apparent ill effects. Extrapolating from patients who were already seriously unwell to normal healthy individuals is ill advised.

This morning my muesli and strawberries tasted just great with the addition of probiotic yoghurt!