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Food Protection Trends
Abstracts - May 2003
The Microbiological Composition and Related Hygiene
Practices Associated with a South African Primary School Feeding Program
Survey of Mayonnaise-based Salads for Microbial Safety and
Quality
Eleven-year Trends of Microbiological Quality in Bulk Tank
Milk
The Microbiological Composition and
Related Hygiene Practices Associated with a South African Primary School Feeding
Program
PIERRE VENTER,* RYK J. F. LUES, JUGEN M. MANYATSA, BOITUMELO
M. MOALUSI, and HERBERT M. NOE
School of Environmental Development and Agriculture, P/Bag
X20539, Technikon Free State, Bloemfontein, 9300, South Africa
SUMMARY
Samples were collected from 46 schools participating in the PSNP (Primary
Schools Nutrition Program) in the Free State Province, South Africa, and analyzed
for total counts, Gram distribution, presumptive Salmonella, Escherichia coli, Staphylococcus aureus, aerobic and anaerobic
spore forming bacteria. A survey was also conducted on the premises, among
food handlers and pupils, regarding facility design, food handling practices
and personal hygiene. The average total mesophilic counts from children’s and
food handlers’ hands were respectively, 19.5 and 21.8 CFU/surface, while counts
for working surfaces and utensils ranged between 3 and 6 CFU/cm2. The
prevalence of Escherichia coli (51.64% occurrence among the Gram-negative colonies)
on food handlers’ hands and Staphylococcus aureus (50.83% representation
among Gram-positive colonies) on table surfaces were relatively high. Numbers
of Salmonella and aerobic and anaerobic spore-forming bacteria were relatively
low in all samples. The facilities and practices were sufficient in some schools,
whereas in a small number of rural schools, basic infrastructure such as toilet
facilities were lacking. In particular, hand wash facilities, cleanable
working surfaces and rodent proofing were inadequate. In all samples the total
aerobic plate counts were relatively low compared with the national standard
for working surfaces (100 CFU/cm2) as guideline; however, the distinct
composition of the population in terms of pathogens was noteworthy. Implementing
some measures and providing at least the minimum of facilities should go a long
way toward improving the general microbiological quality. Recommended improvements
include: (1) Use of appropriate detergents containing disinfectant, inorganic
washable surfaces, gloves and plastic aprons; (2) discontinuation of the practice
of using school desks for the purpose of education and for serving food; and
(3) education of children and food handlers on aspects of food hygiene and personal
hygiene.
Survey of Mayonnaise-based Salads for
Microbial Safety and Quality
Vanessa L. Bornemeier-1, Julie A. Albrecht-1,* and
Susan S. Sumner-2
1-Department of Nutritional Science & Dietetics, University
of Nebraska, Lincoln, NE 68583-0807,
2-Department of Food Science, Virginia Polytechnical Institute
and State University, Blacksburg, VA 24061, USA
SUMMARY
The objective of this study was to survey the safety of mayonnaise-based salads
available in grocery store delis for potential contamination with Staphylococcus
aureus and Listeria monocytogenes. Three mayonnaise-based salads
(potato, macaroni, and krab [surimi processed fish]) purchased from three grocery-store
deli operations in Lincoln, Nebraska were analyzed for total aerobic plate count,
L. monocytogenes, and S. aureus. The temperature of the salads
was measured upon purchase, and pH measurements were made within one-half hour
after purchase. The salads were assessed visually and food handling practices
of deli personnel were observed. The temperatures of the salads ranged
from 37.9°F to 46.4°F (3.3 to 8.0°C). The pH ranges for the salads were:
potato, 4.13 to 4.56; macaroni, 3.99 to 4.53; krab, 4.48 to 5.79. Total
aerobic plate counts expressed as log10 units ranged from 2.97 to 3.79.
Most Probable Number expressed as log10 units for S. aureus ranged from
1.36 to 2.47 for the salads. Three krab salad samples and one macaroni
salad sample were found to have coagulase positive S. aureus. L. monocytogenes
was not found in any samples. Garnishes were found on 86% of the salads
surveyed, and gloves and hairnets were not worn by any of the foodservice personnel
at the deli operations surveyed. Visual assessment of the salads at the time
of purchase revealed crust on the surface of salads, discolored ingredients,
and watery consistency. Results of this survey indicate that temperature conditions
for all three salads and the pH range for krab salad could support growth of
pathogenic microorganisms. Food handling and storage practices indicate that
HACCP procedures are necessary to ensure the safety of salad bar operations.
Eleven-year Trends of Microbiological
Quality in Bulk Tank Milk
Michael Costello,-1 Min-Suk Rhee,-2 Marc P. Bates,-1Stephanie
Clark,-1 Lloyd O. Luedecke,-1 andDong-Hyun Kang-1*
1-Department of Food Science and Human Nutrition, Washington
State University, Pullman, Washington 99164-6376, USA;
2-Department of Food Science, Korea University, Seoul, Korea
SUMMARY
The objectives were (1) to
report the microbiological quality of bulk tank milk (BTM) from a long-term
series of data collection, (2) to investigate the transport sanitation and
seasonal effect on the microbiological quality of BTM, and (3) to evaluate
correlations among the microbiological quality traits. Samples (n
= 545) were collected weekly from one herd and one bulk tank in Washington from
January 1990 to December 2000. To
determine the transport sanitation, additional samples (n = 288) were serially obtained from the farm, truck, and creamery
bulk tank. Samples were analyzed by standard plate count (SPC), coliform count,
and somatic cell count (SCC). Throughout the 11 years, the mean values were
5,600 (for SPC) 500 CFU/ml, (for coliforms) and 200,000 cells/ml, (for SCC). The
relationships among microbiological traits were of low to moderate significance.
In terms of sudden elevations of SPC, coliform numbers, and SCC, values for
individual samples revealed no strong association with other variables. Our
results indicate that those traits could not be used as predictors to estimate
any other index. A significant
increase of SPC (P < 0.05) was
observed as transfer increased; the increase was approximately 1,000 CFU/ml
between farm tank and creamery bulk tank. Higher (P
< 0.05) SPC were observed in winter than in spring and summer. The SCC was
highest (P < 0.05) in summer. The findings suggest that microbiological
quality of BTM may be affected by factors such as transport system and season.
This information may assist the dairy industry in examining the long-term trends
of microbiological quality in BTM throughout the United States.
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