Wednesday, March 12, 2014

Unsafe Hospital Food? There is a greater concern

A couple of days ago, I came across a reference to a report that claimed 85% of raw chicken delivered to the University Hospital in Geneva tested positive for strains of Escherichia coli resistant to extended-spectrum beta lactam antibiotics. These antibiotics belong to the penicillin family. The original study was published in  Infection Control and Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America.  (Unfortunately, when I tried it, the link was broken).
Apparently, there were workers in the hospital kitchen who tested positive to carriage of the ESBL E. coli, however, the frequency was no greater than in the general population.

The finding of the high rate of contamination with ESBL resistant bacteria in the raw chickens is a concern, not because patients were at risk, but because it indicates that the poultry flocks had probably been exposed to antibiotics that are still used in therapy.  Proper procedures in the kitchens should ensure that the contaminating bacteria are destroyed and that cross contamination from raw meat to cooked or fresh foods is controlled.

The use of antibiotics in animal husbandry is leading to increased incidence of antibiotic resistant bacteria.  See my previous posts on antibiotics:    
et seq.

When I gave my inaugural lecture as Professor of Food Microbiology, I reviewed the developments in microbiology that led to the discovery and development of penicillin.  Before the advent of this antibiotic, a simple scratch with a rose thorn could be a death sentence if the scratch became infected.  It would be a catastrophe if we returned to those days because we had squandered our slim advantage over the pathogenic bacteria for short term financial gains by the animal rearing industries.

Sunday, March 2, 2014

To flush or not to flush ...

This post was originally published on 7th February, 2011.  I accidentally deleted it while trying to answer a question from a reader.  Here it is again.

No, this one isn't about faecal bacteria, at least not directly.

Our major TV news broadcaster was guilty over the weekend of a dreadful beat-up on the use of gas mixtures to extend the shelf life of fresh meat.  Under the banner of "How safe is your meat?", the channel made a big deal of the use of gas mixtures containing carbon dioxide to inhibit bacteria on the meat.  They implied that suppliers were trying to pass off old meat as "fresh" and that the process was used to make the meat look redder and thus deceive the consumer into thinking that the meat was fresher.  A further implication of the banner was that gas flushed meat is unsafe.  Must have been a slow news day.

Meat technologists and microbiologists have known for many years that gas mixtures containing carbon dioxide inhibit bacteria, such asPseudomonaswhich are responsible for the development of slime and odours on meat stored under refrigerated conditions.  The gas also inhibits many pathogens, which may potentially cause disease.  

Consumers interviewed in supermarkets said that the meat should be labeled to indicate that it had been gas flushed.  Of course, one supermarket chain said they would do this if customers wanted it, while another tried to take the high ground and claim that they would never gas flush meat.

This is all playing on the ignorance of many consumers about food technology and food safety.  Certainly the meat keeps longer when gas flushed. Why does meat normally have such a short shelf life?  Because some bacteria can grow under refrigeration conditions and turn the meat slimy or produce odours that consumers find objectionable.

Should we ignore and reject the many years of research on food preservation?  Should we perhaps go back to taking meat home wrapped in paper and cooking it the same day?  That's "natural".  Should we reject vacuum packaging - it's not natural, but in fact works in a very similar way to gas flushing.  Consumers have demanded longer shelf life in all sorts of foods - meat, strawberries, smoked mussels, cakes and pastries.  In response, food technologists have developed ways to deliver such foods and these techniques involve preservative chemicals, vacuum packaging, pasteurisation and gas flushing (modified atmospheres).  If we are prepared to go back to foods with a shelf life of just a few days, we can reject gas flushing and other technologies.

If consumers are really concerned about gas flushing, they can recognise flushed packs by the fact that the film is sealed to the tray, or in some cases, such as gas flushed bakery goods, the package looks like a pillow.

Me?  Well, I'll happily buy carbon dioxide flushed meat - it keeps longer and in some cases looks better.