bacterial contamination of blenderized

8/4/2019 Bacterial Contamination of Blenderized

1/23

BACTERIAL

CONTAMINATION OF

BLENDERIZED

WHOLE FOOD ANDCOMMERCIAL ENTERALTUBE

FEEDINGS IN THEPHILIPPINES

Reviewer no.4


2/23

Introduction

Enteral feedings provide a favourable mediumfor exponential growth of microorganisms

Inoculated a commercial feeding with a single

Staphylococcus aureus organism. After 24 h at37C, a viable count of 8.2105 organisms/mLwas obtained.

Contaminated feedings increase the risk ofnosocomial infections such as diarrhoea,pneumonia and septicaemia


3/23

The feeding yielded heavy growths of Bacilluscereus, Escherichia coli, Streptococcusfaecalis and a Pseudomonas species.


4/23

Mechanisms by which tube

feeding contamination can occur

Raw ingredients used in enteral feedings arenot sterile.

Feedings may be exposed to bacterial

contamination during the preparation andmixing of ingredients,

the dilution or decanting of feedings into the

feeding container, and the assembly and handling of the feeding

system


5/23

Cross-contamination in hospitals occursmainly via hands

Reports of nurses testing the temperature of

enteral feedings with their fingersdemonstrates that not all hospital personnelare aware of the potential mechanisms of

feeding contamination


6/23

Materials and methods

Four acute-care hospitals in Manila,Philippines participated in the study

two different tube feeding recipes, one

representing a `standard' diet and the other, amodified diet of the hospital's choice (e.g.`diabetic', sodium-restricted', anti-

diarrhoeal').


7/23

All feedings were maintained at roomtemperature for 4 h after preparation tosimulate a typical tube feeding administration

time. The mean ambient temperature range inthe hospitals was 2631C.

Immediately after preparation and at 1, 2 and

4 h following preparation,


8/23

Standard plate counts (by pour platemethod)12 and coliform counts (by MPNmethod)13 were obtained.

Tube feeding samples at three of the hospitals(B, C and D) were prepared from blendedfoods suchas meat, fruit and vegetables, whiletwo hospitals (A and B) used a commercialpowdered formula as a base to which wateralone or water and fruit was added.


9/23

Results

Bacterial contamination appeared to be relatedto the nature of the formula ingredients used

The natural food feeds provided significantly

higher mean standard plate counts than thecommercial powder formula feeds at 1 and 2 hafter preparation


10/23

Using a definition of `unacceptable'contamination as a standard plate countgreater than 103 cfu/mL at 4 h,9,14 100% of

the feeds made from natural foods wereunacceptably contaminated, while 33% of thefeeds made with reconstituted commercialpowder were unacceptably contaminated

(P.0.017).


11/23

Fourteen samples (58%) were positive forcoliforms (coliform count of at least 1MPN/g)immediately after preparation. Two samples

(8%) had counts of 510MPN/g and ninesamples (38%) had counts greater than10MPN/g.

Mean coliform counts increased significantlyover time (P.0.0005).


12/23

Discussion

Enteral nutrition is essential in the care ofpatients who are unable or unwilling to eat.

Compared with parenteral nutrition, enteral

nutrition is more cost-effective, helps maintaingastrointestinal tract structure and function,and is generally associated with fewercomplications


13/23

Commercial, ready-to-use feedings which aresterile at the time of decanting have beenavailable for over 20 years. These feedings

have virtually eliminated blenderized feedingsin the developed nations of North America andEurope


14/23

However, blenderized feedings continue to beused in many parts of the world for economicor cultural reasons, especially in developing

nations, including the Philippines Of particularconcern,many of the developing nations arelocated in warmer climates where highambient temperatures might be expected to

assist in bacterial proliferation in contaminatedenteral feeding solutions.


15/23

potential complication of enteral

feeding

microbial contamination of the solution

Contamination of utensils used in feedingpreparation, such as blenders, measuring jugs

and dish cloths, are an important source ofpathogens.

The use of sterile, disposable supplies is rarein feeding preparation.

Handling of any part of the feedingadministration apparatus during assembly oruse may result in contamination,which can bereduced by meticulous handwashing


16/23

However, even with careful handling, sterilefeedings can become contaminated uponadministration; putative sources being hospital

staff, ventilators, suction apparatus, washbowls and the patient him/ herself(endogenous flora of the gut, upper respiratorytract, and skin).

Contaminated feedings can result inmorbidityand mortality. Gastrointestinal, as well asextraintestinal, nosocomial infections can

result.


17/23

Hospitalized patients can be at enhanced riskof morbidity and mortality due toimmunosuppression secondary to cancer,human immunodeficiency virus infection,thermal injuries, diabetes, severe trauma, ordrug therapy.

The use of gastric acid suppressing

medications may increase the risk of infectiondue to elimination of the protective gastric acidbarrier.

Infections due to contaminated tube feedings

can also increase hospital and intensive care


18/23

Other recommendations include the use ofsterile (commercial) feedings, wheneverpossible, in `at risk' individuals and aerobic

plate counts of non-sterile feeds of less than10 microorganisms/ mL at the start ofadministration and less than 103/mL at theend.

The US Centers for Disease Control andPrevention cite a count of 105 micro-organisms/mL as a threshold for foodborne

disease outbreaks.


19/23

Results from the present study suggest thatthe majority of feeding solutions prepared inthe four acute-care hospitals in the Philippines

were unacceptable from the perspective ofbacterial contamination.

Immediately afterpreparation,96%of sampleshad unacceptable standard plate countsgreater than 101 cfu/g.


20/23

The 4-h incubation period of the present studywas chosen based upon recommendations forthe administration time ofnon-sterilized or

diluted feedings. In practice, this 4-h period may be unrealistic

when transit and storage times are considered.Even limiting administration times to 4 h in thepresent study did not reduce the risk of feedingcontamination.


21/23

Of interest, the present study suggested that coliformcontamination was related to the site of preparation(Hospital D vs. the other hospitals) while overallbacterial contamination (standard plate counts) wasrelated to feeding composition.

As coliform contamination is associated with thefaecal hand route of transmission, one mightspeculate that preparation technique was mostmeticulous at Hospital D.

The fact that the standard plate counts were similarbetween hospitals suggests that the source ofcontamination was the ingredients of the feedings. Atall four hospitals, water used in feeding preparationwas an unlikely source of contaminationcas it wasboiled before use.


22/23

Given the nature of the potential sources of feedingcontamination, it is clear that the less the degree ofmanipulation, the lower should be the risk ofcontamination.

Thus commercial feeds delivered in prefilled or closedsystems which require no handling should be thesafest from the perspective of microbial contaminationfollowed by decanted, non-diluted commercial feeds,then by decanted or powdered commercial formulasundergoing manipulation (e.g. dilution, reconstitution,addition of other ingredients).

All commercial feeding solutions should be superior toblenderized natural foods from the perspective of

microbial safety.


23/23

Measures should be taken to improve the microbialquality of enteral feedings so as to reduce the risk ofnosocomial infections.

These include the development of protocols for clean

technique in the preparation, handling and storage offeedings and cleaning of preparation equipment.Personnel must adhere to proper administrationtechniques, including meticulous handwashing andlimitation of administration time.

The use of commercial products, particularly thoseadministered by means of a closed system, mayprovide an additional margin of safety for hospitalizedpatients.

bacterial contamination of blenderized

Documents