Microbiological Quality of Noodles
July - September 1998
Report prepared by Geoff Millard
This survey was designed to determine the microbiological status of noodles available in the ACT and to assess any change in microbiological status of Hokkien noddles since the last survey.
Noodles are widely available in the ACT and a previous survey conducted on Pasta and Moist Noodles in 1997 highlighted Hokkien noodles as being a problem. A number of brands of Hokkein noodles had high Standard Plate Counts (SPCs) and were positive for E. coli, Coagulase positive Staphylococcus and B. cereus. As the current survey concentrated on noodles only, it was not considered advisable to compare the two surveys in total. However, a comparison of the Hokkien noodle components is possible.
The Australia New Zealand Food Authority Food Standards Code does not have standards for these products.
Between July and September 1998 the members of the Microbiology Unit of the ACT Government Analytical Laboratory (ACTGAL) collected a total of 71 samples of 38 different types of pre packaged noodles. These noodles were collected from 14 retail outlets across ACT and had been stored under refrigeration. As a previous survey had identified Hokkien style noodles as having high SPCs they were preferentially surveyed and consisted of 38% of the total number collected. These noodles are part cooked when purchased and are designed to be fully cooked, prior to consumption.
All samples were tested for SPC, E. coli, Coagulase positive Staphylococcus, Bacillus cereus and for the Presence/Absence of Salmonella. Nine of the staph counts were lost due to a laboratory accident.
Standard Plate Count
Graph 1 Distribution of SPCs
As can be seen from Graph 1;
- 18 (25.4%) samples having a value <1000 cfu/gm,
- 15(21.1%) samples between >1000 -<1,000,000 cfu/gm,
14 (19.7%) samples between 1 and 10 million cfu/gm,
- 19 (26.7%) samples between 10 and 100 million cfu/gm and
- 5 (7%)> 100 million cfu/gm.
The median SPC value was 1,800,000 colony-forming units per gram (cfu/gm).
E. coli was not detected in any of the 71 samples tested.
Coagulase Positive Staphylococcus
Coagulase-positive Staphylococcus was not detected in any of the 62 samples tested.
Bacillus cereus was not detected in any of the 71 samples tested.
Salmonella was not detected in any of the 71 samples tested.
The SPC distributions were similar in both surveys. As 53.5% of samples from the 1998 survey had a SPC > 1,000,000 cfu/gm, the indication is that the processing/storage of these samples is not as good as it could be. The product is however designed to be cooked prior to consumption and this cooking process in most cases should lower the SPC to acceptable levels, ie. below 1,000,000.
Of the four brands of Hokkien noodles having poor microbiological results in the previous survey only three were available for analysis during the 1998 survey. The 1998 survey did not detect any pathogens in any sample tested including the Hokkein noodles. It therefore appears that an improvement has occurred in the Hokkein noodles over the year.
This survey has identified that an improvement has occurred in the quality of Hokkien noodles sold in the ACT. The microbial quality of the other types tested of noodles is satisfactory.