Microbiological Quality and the Inability of Proteolytic Clostridium botulinum To Produce Toxin in Film-Packaged Fresh-Cut Cabbage and Lettuce

1998 ◽  
Vol 61 (9) ◽  
pp. 1148-1153 ◽  
Author(s):  
Y.-Y. HAO ◽  
R. E. BRACKETT ◽  
L. R. BEUCHAT ◽  
M. P. DOYLE
Keyword(s):  
Clostridium Botulinum ◽  
Microbiological Quality ◽  
Microbial Populations ◽  
Mouse Bioassay ◽  
Psychrotrophic Bacteria ◽  
Anaerobic Microorganisms ◽  
Significant Difference ◽  
Yeasts And Molds ◽  
Aerobic And Anaerobic

The production of toxin by a 10-strain mixture of proteolytic Clostridium botulinum in fresh produce packaged in polyethylene films having high (7,000 cc/m2/24 h; HOTR) and low (3,000 cc/m2/24 h; LOTR) relative oxygen permeability was determined. Shredded cabbage and lettuce inoculated with ~102 spores/g were placed in bags composed of the two films (1.4 kg/bag), and the bags were then vacuum sealed. Produce was stored at 4, 13, and 21°C for up to 21 (cabbage) or 28 (lettuce) days and analyzed periodically. At each sampling time, the gas composition within the bags, pH of the produce, and microbial populations (total aerobic and anaerobic microorganisms, lactic acid bacteria, psychrotrophic bacteria, and yeasts and molds) were determined. In addition, the presence of botulinal toxin was determined using the standard U.S. Food and Drug Administration mouse bioassay protocol. Bags made of HOTR film prolonged sensory quality of cabbage and lettuce, especially at 13 and 4°C. Packaging material had an effect on the growth of various groups of microorganisms; however, there was not a general trend. For example, lettuce packaged in HOTR bags had higher aerobic microbial populations than that packed in LOTR, but no significant difference (P ≤ 0.05) was observed with cabbage. Growth of psychrotrophic bacteria was greater in vegetables packaged in HOTR film while growth of yeasts and molds was not affected by either packaging film. Most differences in microbial populations in produce packaged in LOTR and HOTR films were less than 1 log10 CFU/g. Botulinal toxin was not detected in cabbage or lettuce packaged in either film or stored under any test condition.

Microbiological Quality and Production of Botulinal Toxin in Film-Packaged Broccoli, Carrots, and Green Beans

1999 ◽  
Vol 62 (5) ◽  
pp. 499-508 ◽  
Author(s):  
Y.-Y. HAO ◽  
R. E. BRACKETT ◽  
L. R. BEUCHAT ◽  
M. P. DOYLE
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gas Permeability ◽  
Microbiological Quality ◽  
Packaging Material ◽  
Green Beans ◽  
Psychrotrophic Bacteria ◽  
Anaerobic Microorganisms ◽  
Yeasts And Molds

The production of toxin by a 10-strain mixture of proteolytic Clostridium botulinum in fresh produce packaged in polyethylene films with different oxygen permeability was determined. Broccoli florets, shredded carrots, and green beans inoculated with approximately 102 C. botulinum spores per g were placed in bags (1.4 kg per bag) composed of four films with different oxygen transmission rates (OTRs). Broccoli was packaged in bags with OTRs of 3 (7,000 cm3/m2/24 h) and 4 (16,000 cm3/m2/24 h), and green beans were packaged in bags with OTRs of 2 (6,000 cm3/m2/24 h) and 4. Broccoli and green beans in bags were compressed and heat-sealed. Shredded carrots were packaged in bags with OTRs of 1 (3,000 cm3/m2/24 h) and 3 and vacuum-sealed. Produce was stored at 4, 13, and 21°C for up to 27 (broccoli) or 28 (carrots and green bean) days and analyzed periodically. At each sampling time, gas composition within the bags, pH of the produce, microbial populations (total aerobic and anaerobic microorganisms, lactic acid bacteria, psychrotrophic bacteria, yeasts, and molds), and the presence or absence of botulinal toxin were determined. Packaging material affected the quality of vegetables, especially broccoli stored at 4 and 13°C. For example, broccoli was scored as “good” after 22 days at 4°C when it was packaged in film with higher gas permeability (OTR of 4), whereas broccoli appeared to be in “poor” condition when packaged in film with lower gas permeability (OTR of 3). With the exception of lactic acid bacteria, packaging material did not noticeably influence the growth of microorganisms. Lactic acid bacteria grew better in broccoli packaged in bags with an OTR of 3 than in those with an OTR of 4 at all temperatures. Botulinal toxin was detected in broccoli packaged in bags with an OTR of 3 and stored at 13°C for 21 days and in those with an OTR of 4 and 3 and stored at 21°C for 10 days. All toxic samples were visibly spoiled. Toxin was not detected in produce packaged under any other test conditions.

Study of the Microbial Ecology of Wild and Aquacultured Tunisian Fresh Fish

2011 ◽  
Vol 74 (10) ◽  
pp. 1762-1768 ◽  
Author(s):  
MOUNA BOULARES ◽  
LOBNA MEJRI ◽  
MNASSER HASSOUNA
Keyword(s):  
Aeromonas Hydrophila ◽  
Microbiological Quality ◽  
Common Species ◽  
Microbial Populations ◽  
Plate Count ◽  
Gram Negative Bacteria ◽  
Fresh Fish ◽  
Psychrotrophic Bacteria ◽  
Aerobic Plate Count

Eighty samples of fresh fish were collected in Tunisia and analyzed for microbial load. Quality and hygienic safety of the meat and intestines of wild and aquacultured fresh fish were determined. The mesophilic aerobic plate count and populations of psychrotrophic lactic acid bacteria (LAB) and other psychrotrophic bacteria ranged from 5.67 to 7.29, 4.51 to 6, and 5.07 to 6.21 log CFU/g, respectively. For all microbiological determinations, bacterial counts were lower in meat than in the intestines of fresh fish. For all samples lower microbial populations were found in most of the wild fish than in the aquacultured fish. No isolates of the pathogenic genera Salmonella and Listeria were detected in any sample. Among the 160 strains of biopreservative psychrotrophic LAB and the 150 strains of spoilage psychrotrophic gram-negative bacteria identified by biochemical and molecular methods, Lactobacillus (six species) and Pseudomonas (six species) predominated. Lactococcus, Leuconostoc, Carnobacterium (C. piscicola and C. divergens), Aeromonas, and Photobacterium were the most common genera, and Lactococcus lactis, Lactobacillus plantarum, Pseudomonas fluorescens, and Aeromonas hydrophila were the most common species. These findings indicate that the microbiological quality of fresh fish in Tunisia can be preserved by controlling pathogenic and psychrotrophic bacteria.

Microbiological Quality of Commercial Tofu

1984 ◽  
Vol 47 (3) ◽  
pp. 177-181 ◽  
Author(s):  
T. G. REHBERGER ◽  
L. A. WILSON ◽  
B. A. GLATZ
Keyword(s):  
Microbiological Quality ◽  
Plate Count ◽  
Microbial Counts ◽  
Colony Forming Units ◽  
Low Levels ◽  
Microbial Groups ◽  
Yeasts And Molds ◽  
Processing Techniques

A study was done to investigate the microbiological quality of commercial tofu available in local retail outlets. A sampling method was first developed to obtain accurate and representative microbial counts of individual pieces of tofu. Plate count determination of total aerobic organisms, psychrotrophs, coliforms, sporeformers, yeasts and molds, and staphylococci were made on 60 tofu samples (representing three lots each of four different brands) obtained within 24 h after delivery to the retail store. In addition, for two brands that provided manufacturer's pull dates, the same microbial counts were obtained for samples stored in the laboratory at 10°C until the pull date. Of the tofu sampled immediately after purchase, 83% of the lots tested had total counts greater than 106 colony-forming units (CFU)/g and psychrotrophic counts greater than 104 CFU/g. In addition, 67% of the lots tested had confirmed coliform counts greater than 103 CFU/g. Very low levels (less than 10 CFU/g) of all other microbial groups tested for were found in the majority of lots. Samples held until the manufacturer's pull date contained higher total and psychrotrophic counts but lower or stable counts of other organisms compared with samples tested immediately after purchase. To improve the microbiological quality of tofu, processors need to reduce initial loads by improving sanitation and processing techniques, and retailers should provide more consistent and colder refrigerated storage.

scholarly journals Quality and shelf life of packaged fresh sliced mushrooms stored at two different temperatures

2008 ◽  
Vol 15 (4) ◽  
pp. 414 ◽  
Author(s):  
E. GONZÁLEZ-FANDOS ◽  
A. SIMON JIMENES ◽  
V. TOBAR PARDO
Keyword(s):  
Carbon Dioxide ◽  
Shelf Life ◽  
Agaricus Bisporus ◽  
Microbiological Quality ◽  
Air Atmosphere ◽  
Pvc Film ◽  
Different Temperatures ◽  
Aerobic And Anaerobic ◽  
Quality And Shelf Life

The sensory and microbiological quality of sliced mushrooms (Agaricus bisporus L.) packaged in films of perforated and non-perforated PVC and stored at 3 and 9ºC, was studied. The carbon dioxide and oxygen content inside the packages, colour, weight loss, sensory attributes, mesophiles, Pseudomonas, Enterobacteriaceae, aerobic and anaerobic spore formers were determined. The atmosphere generated with the perforated PVC film was similar to that of air atmosphere at 3 or 9ºC. T.he non-perforated PVC film generated inside the packages CO2 : O2 concentrations of 3.4% : 8.1% at 3ºC and CO2 : O2 concentrations of 4.5% : 0.15% at 9ºC. Browning of mushrooms was lower at 3 than at 9ºC. The quality of sliced mushrooms packaged in perforated PVC and stored at 3ºC was adequate after 9 days. However, at 9ºC, the slice deformation and brown blotches incidence were severe after 9 days. The atmosphere generated with non-perforated PVC inhibited aerobic microorganism growth compared to mushrooms packaged in perforated PVC. At 3ºC, the shelf life of mushrooms packaged in non perforated PVC was around 13 days. However, the extremely low O2 atmospheres generated at 9ºC was accompanied by off-odours and growth of anaerobic spore formers, although the appearance of sliced mushrooms was acceptable.;

scholarly journals Changes of Quality of Minimally-Processed Pineapple (Ananas comosus, var. ‘Queen Victoria’) during Cold Storage: Fungi in the Leading Role

2020 ◽  
Vol 8 (2) ◽  
pp. 185 ◽  
Author(s):  
Charlène Leneveu-Jenvrin ◽  
Baptiste Quentin ◽  
Sophie Assemat ◽  
Mathilde Hoarau ◽  
Jean-Christophe Meile ◽  
...  
Keyword(s):  
Cold Storage ◽  
Microbiological Quality ◽  
Fungal Species ◽  
Ananas Comosus ◽  
Minimally Processed ◽  
Leading Role ◽  
Queen Victoria ◽  
Processing Step ◽  
Yeasts And Molds

Minimally-processed pineapple stored under refrigerated conditions is highly perishable. We aimed to characterize the evolution of physicochemical, sensory and microbiological quality during cold storage. Pineapple batches were sampled from several locations in Reunion Island and then minimally processed. In the processing step, the variability of firmness and counts of yeasts and molds were observed. Moreover, correlations between the sampling season and pH and b* color component, as well as between fungal population and b* parameter were observed. During storage, the visual aspect of pineapple cuts changed to brown and shiny, whereas olfactive descriptors shifted from fruity descriptors and fresh to fermented, alcoholic and milky. The values for pH, TA and TSS did not significantly vary according to storage time. A decrease in firmness and C* color parameter was observed. Yeast and mold counts were significantly higher after 7 days of storage. The diversity in yeasts and molds was mainly dependent on the considered batches observed from PCR-DGGE profiles. Fungal species were isolated from spoiled pineapple cuts. The implication of Penicilllium citrtrinum, Talaromyces amestolkiae, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, and Meyerozyma caribbica in the spoilage of minimally-processed pineapple cuts was further demonstrated.

A Bacteriological Survey of Raw Ground Beef1

1977 ◽  
Vol 40 (11) ◽  
pp. 790-794 ◽  
Author(s):  
JAMES F. FOSTER ◽  
JAMES L. FOWLER ◽  
WARREN C. LADIGES
Keyword(s):  
Escherichia Coli ◽  
Microbiological Quality ◽  
Retail Store ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Fecal Streptococci ◽  
Plate Counts ◽  
Aerobic And Anaerobic

The microbiological quality of 150 units of raw ground beef obtained from a local retail store was determined. The range of aerobic plate counts was from 6.9 × 104 to 8.3 × 107/g. By using the most probable number method 96.7% of the 150 units were positive for coliforms, 94.7% for Escherichia coli and 61.3% for Staphylococcus aureus. By the plate methods, 99.3% of the units were positive for fecal streptococci and 56% were positive for Clostridium perfringens. No salmonellae were isolated. Aerobic and anaerobic organisms were isolated and identified. E. coli was the most frequently isolated aerobe followed by organisms in the Klebsiella-Enterobacter group. Among the anaerobic isolates, C. perfringens was the organism most frequently encountered.

scholarly journals Physicochemical Characteristics and Microbiological Quality of Honey Produced in Benin

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
François Ezin Azonwade ◽  
Armand Paraïso ◽  
Cokou P. Agbangnan Dossa ◽  
Victorien T. Dougnon ◽  
Christine N’tcha ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Microbiological Quality ◽  
Physicochemical Characteristics ◽  
Ash Content ◽  
International Standards ◽  
Free Acidity ◽  
Total Sugars ◽  
Microbiological Characteristics ◽  
Significant Difference

Honey is a very complex biological product. It has great diversity, giving it a multitude of properties, both nutritionally and therapeutically. This study aimed to study the physicochemical and microbiological characteristics of honeys collected during the dry and rainy seasons in the different phytogeographical areas of Benin. The study revealed that all honeys had pH, water content, electrical conductivity, ash content, free acidity, total sugars, and reducing sugars, respectively, ranging within 3.65–4.09; 12.07–13.16%; 530.25–698.50 μs/cm; 0.42–0.53%; 35.67–40.52 meq/kg; 60–70%; and 58–70%. Moisture content, total sugars, and reducing sugars varied very significantly (p<0.05top<0.001) from one area to another and from one season to another. However, only the production season has a significant influence (p<0.05) on the pH of the honey. With regard to the ash content, free acidity, and electrical conduction, no significant difference (p>0.05) between the zones or between the seasons was observed. The results of the microbiological characterization showed that there is heterogeneity in the microbial load. These results have shown that these honeys meet international standards and their characterization will make it possible to obtain Beninese quality labels.

Chemical and Microbiological Quality of Raw Milk Produced by Smallholder Farmers in Zimbabwe

1996 ◽  
Vol 59 (9) ◽  
pp. 984-987 ◽  
Author(s):  
A. N. MUTUKUMIRA ◽  
S. B. FERESU ◽  
J. A. NARVHUS ◽  
R. K. ABRAHAMSEN
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Smallholder Farmers ◽  
Microbiological Quality ◽  
Titratable Acidity ◽  
Raw Milk ◽  
Chemical Characteristics ◽  
Yeasts And Molds ◽  
Microbiological Analyses

Chemical and microbiological analyses were carried out on 10 samples of raw milk collected over 6 months from the Nharira/Lancashire Milk Collection Center. The milk center is run by smallholder farmers. The purpose of the study was to evaluate the quality of the raw milk delivered to the milk collection center. The average chemical characteristics of the milk were (%): titratable acidity expressed as lactic acid, 0.21; total protein, 3.19; fat, 3.52; total solids, 11.76; and solids not fat, 8.25; the pH varied from 6.15 to 6.65. There were large variations in the microbiological composition of the raw milk with total aerobic counts ranging from 6.2 × 103 to 7.8 × 107 CFU/ml, coli forms from 3.2 × 102 to 2.3 × 105, and lactic acid bacteria from less than 1 × 103 to 2.9 × 106 CFU/ml. Yeasts and molds were less than 100 CFU/ml in 7 of the 10 samples analyzed.

Microbiological Quality of Frozen Cream-Type Pies Sold in Canada

1983 ◽  
Vol 46 (1) ◽  
pp. 34-40 ◽  
Author(s):  
E. C. D. TODD ◽  
G. A. JARVIS ◽  
K. F. WEISS ◽  
G. W. RIEDEL ◽  
S. CHARBONNEAU
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Microbiological Quality ◽  
The United States ◽  
National Guidelines ◽  
E Coli ◽  
Yeasts And Molds

Ten types of frozen cream-type pies, manufactured in Canada and imported from the United States, were analyzed for aerobic colony counts, yeasts and molds, coliforms, Escherichia coli, Staphylococcus aureus and Salmonella. The variations in counts depended more on the manufacturer than on the type of pie and the ingredients used. Five of the 465 examined pies had an excess of 105 aerobic colony counts/g, whereas the median value for all the pies examined was between 102 and 103 CFU/g. E. coli and S. aureus were present in few pies, mainly made by one manufacturer, but there was no correlation between high aerobic colony counts and these organisms. Salmonella was not found in any of the pies. Percentage distributions of the estimated ‘population’ of pies available nationally at the time of the survey were statistically determined. These were then compared with suggested national guidelines in the form of a three-class acceptance plan based on United States surveys and desirable manufacturing practices. These indicate that pies should contain aerobic colony counts of &lt;50,000/g, yeast and mold counts of &lt;500/g, S. aureus counts of &lt;100/g, coliform counts of &lt;50/g, E. coli counts of &lt;10/g, and no Salmonella. Three of the six manufacturers would have had an estimated 5.4 to 32.6% of lots in excess of the guidelines at the time of the survey.

scholarly journals Microbiological Quality of Salads Served along with Street Foods of Hyderabad, India

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Alekhya Sabbithi ◽  
R. Naveen Kumar ◽  
L. Kashinath ◽  
V. Bhaskar ◽  
V. Sudershan Rao
Keyword(s):  
Staphylococcus Aureus ◽  
Microbiological Quality ◽  
Food Handlers ◽  
Street Vendors ◽  
Street Food ◽  
Significant Difference ◽  
The Status ◽  
Salad Vegetables

A study has been done to analyse the microbiological quality of salads served along with street foods of Hyderabad. A total of 163 salad samples, 53 of carrot and 110 of onion samples, were collected from four different zones of Hyderabad. About 74% and 56% hadStaphylococcus aureusin carrots and onions, respectively. Fifty-eight percent of carrots and forty-five percent of onions samples containedSalmonella, 68% of carrots and 24% of onions hadYersinia. HACCP study was carried out with 6 street food vendors to identify the source ofSalmonellacontamination in salads. Food handlers were found to be responsible forSalmonellacontamination in salads. The present study revealed the potential hazards of street vended salad vegetables, considering the handling practice usually carried out by vendors. Ninety-eight percent of the vendors did not wash the vegetables before processing and serving while about 56.6% of the vendors did not peel the vegetables. Majority of street vendors’ nails were uncut. A significant difference (P<0.01) was observed inYersiniaspp. andSalmonellaspp. in wet-dirty chopping board when compared to clean-dry chopping board. A significant difference (P<0.05) ofStaphylococcusspp. was observed when the status of cleaning cloth was neat/untidy.

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