Use of Selective Media to Detect Enzyme Production by Microorganisms in Food Products

1975 ◽  
Vol 38 (10) ◽  
pp. 570-572 ◽  
Author(s):  
SANDRA L. ANAGNOSTAKIS ◽  
LESTER HANKIN
Keyword(s):  
Bacterial Growth ◽  
Food Analysis ◽  
Enzyme Production ◽  
Food Products ◽  
Bacterial Populations ◽  
Selective Media ◽  
Keeping Quality ◽  
Degradative Enzymes

Media are described for use in food analysis to detect fungi and bacteria able to excrete extracellular lipases, proteases, pectinases, amylases, and acids. Antibiotics were used to suppress bacterial growth in media that detect fungi. Food products were examined to show the ability of these media to detect contaminating microorganisms able to excrete these enzymes. The possibility that keeping quality of foods could be correlated with numbers of organisms able to excrete these degradative enzymes is discussed. The test media also could be used to obtain total counts of fungal and bacterial populations.

Effect of oxygen on the keeping quality of milk: II. Effect of available oxygen on bacterial spoilage and oxygen uptake

1982 ◽  
Vol 49 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Monika J. A. Schröder
Keyword(s):  
Oxygen Uptake ◽  
Shelf Life ◽  
Bacterial Growth ◽  
Bacterial Count ◽  
Bacterial Activity ◽  
Pasteurized Milk ◽  
Keeping Quality ◽  
Quality Of Milk ◽  
Effect Of Oxygen

SUMMARYThe effect of limiting the amount of O2 present in commercially pasteurized milk on bacterial growth and on the keeping quality of the milk was investigated. No increase in bacterial count of laboratory pasteurized milk during storage for 9 d at 5 °C was observed and O2 consumption due to bacterial activity was low. In commercial pasteurized milk containing post-pasteurization contamination (PPC) growth of strict aerobes was encouraged by high O2 content while that of coliforms was less dependent on O2 level. The amounts of headspace (HS) O2 consumed in milk with PPC growth were large. Reducing the dissolved O2 content of commercial pasteurized milk stored in O2-impermeable containers without HS had little effect on bacterial activity and shelf-life.

scholarly journals Bacteriological tests as indices for the development of off-flavours in cream

1975 ◽  
Vol 75 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Margaret M. Taylor
Keyword(s):  
Bacterial Growth ◽  
The Other ◽  
Keeping Quality ◽  
Bacterial Action

SUMMARYBacteriological tests alone are not capable of predicting the keeping quality of cream, since taints can develop which are due to non-bacterial action. When spoilage is due to bacterial growth, the water agar test was found to be more accurate than the other tests that were examined.

Keeping Quality of Pacific Coast Dogfish

1959 ◽  
Vol 16 (6) ◽  
pp. 791-794 ◽  
Author(s):  
R. H. Moyer ◽  
B. A. Southcott ◽  
E. G. Baker ◽  
H. L. A. Tarr
Keyword(s):  
Pacific Coast ◽  
Sea Water ◽  
Total Volatile ◽  
Bacterial Counts ◽  
Ph Values ◽  
Appreciable Increase ◽  
Muscle Ph ◽  
Keeping Quality ◽  
Viable Bacteria

Pacific coast dogfish (Squalus suckleyi) were held 21 days in ice and in refrigerated sea water with and without added chlortetracycline, viable bacterial counts and volatile bases being determined periodically. Viable bacteria increased sharply after about 14 days but the muscle pH values showed little or no increase. No appreciable increase in the total volatile base or trimethylamine content of the muscle was noted until the fish were stored for more than 2 weeks, and then the increases observed were comparatively small.

scholarly journals Microbiological quality of non-sterile pharmaceuticals in Egypt

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Nourhan Mahrous Ahmed Salem ◽  
Mohamed Abbas Elbarrawy ◽  
Nashwa Fawzy Abd El Moez Azzam
Keyword(s):  
Bacterial Growth ◽  
Stenotrophomonas Maltophilia ◽  
Microbiological Quality ◽  
Pseudomonas Stutzeri ◽  
Dosage Forms ◽  
Aeromonas Salmonicida ◽  
Acceptable Limit ◽  
Organoleptic Characteristics

Abstract Background The context and purpose of the study are as follows: Drug-borne infections may arise from non-adherence to strict microbiological quality of pharmaceuticals products. Moreover, presence of exceeding levels of microorganisms in non-sterile pharmaceuticals may lead to change of their organoleptic characteristics and loss of effectiveness. The aim of the study is to evaluate the microbiological quality of commonly used non-sterile pharmaceuticals in Alexandria, Egypt. Results Average microbiological quality of the studied products, where 17.03% and 19.23 % of samples had exceeded the maximum acceptable limit of TAMC and TYMC, respectively. No E. coli was isolated from oral products. None of S. aureus nor P. aeruginosa were isolated from topical products. Bacterial growth was recovered from 19 (10.44%) of the studied 182 samples, four Bacillus spp. had been recovered from topical products, two P. aeruginosa isolates were recovered from tablets and other two were isolated from syrups dosage forms. Other isolates were Pseudomonas stutzeri, Stenotrophomonas maltophilia, Acinetobacter Achromobacter denitrificans, Ochrobactrum anthropic and Aeromonas salmonicida. Conclusion Average microbiological quality of the tested pharmaceuticals used in Alexandria.

Effect of Modified Atmosphere Packaging on Keeping Quality of Jaggery

Sugar Tech ◽  
2012 ◽  
Vol 15 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Dilip Kumar ◽  
Jarnail Singh ◽  
D. R. Rai ◽  
Mahesh Kumar ◽  
S. Bhatia
Keyword(s):  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Keeping Quality

693. A rejection test for raw milk

1958 ◽  
Vol 25 (1) ◽  
pp. 32-51 ◽  
Author(s):  
Peggy B. Taylor ◽  
L. F. L. Clegg
Keyword(s):  
Lactic Acid ◽  
Ferric Chloride ◽  
Technical Assistance ◽  
Milk Proteins ◽  
Raw Milk ◽  
Ph Change ◽  
Yellow Colour ◽  
A Value ◽  
Keeping Quality

The determination of apparent lactic acid has been used as a basis for a rejection test for raw milk. The method consists of precipitation of milk proteins with barium chloride, sodium hydroxide and zinc sulphate, and the addition of ferric chloride to the filtrate to produce the yellow colour of ferric lactate. Lactic acid is not solely responsible for the production of the yellow colour, which, nevertheless, gives a good relationship with keeping quality of milk (measured as hours to the C.O.B. end-point at 22° C.) and the values have been expressed as ‘apparent lactic acid’.The relationship of winter and summer milks to keeping quality has been studied, and a value of 0·03% apparent lactic acid in milk is equivalent to an average keeping quality of 5¾ and 8½ hr. for winter and summer milks, respectively. A value of 0·03% is recommended as the earliest value of apparent lactic acid at which milk could be rejected.The apparent lactic acid in colostrum and late-lactation milk and in milk from cows suffering from mastitis has been determined, and only in late-lactation milk were the values found to be significantly higher than usual in fresh raw milk, and an inverse relationship between yield and apparent lactic acid is suggested.Permanent glass matching disks have been prepared for use in a Lovibond comparator. This permits the intensity of the yellow colour produced with 1% ferric chloride to be determined and the apparent lactic acid in milk estimated.Grateful acknowledgement is made to the management and staff of the Dairy Department of the Reading Co-operative Society and the Farmer's Clean Milk Dairy, Reading, and local milk producers for supplying samples for experiments; to the N.M.T.S. staff in Reading for help in finding suitable farmers, and to the Dairy Husbandry Department of the N.I.R.D. for information about and samples of abnormal and late-lactation milk. Our particular thanks are due Miss Marie Gruber for technical assistance, to Dr N. J. Berridge for the suggestion and help on the work on pH change as an indication of keeping quality (given in the appendix), and to Dr A. T. R. Mattick for the advice given in this work.

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