Usefulness of the Benzalkon-Crystal Violet-ATP Method for Predicting the Keeping Quality of Pasteurized Milk

1982 ◽  
Vol 45 (10) ◽  
pp. 928-931 ◽  
Author(s):  
G. M. WAES ◽  
R. G. BOSSUYT
Keyword(s):  
Shelf Life ◽  
Crystal Violet ◽  
Quantitative Estimation ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Life Test ◽  
Pasteurized Milk ◽  
Keeping Quality ◽  
Factory Laboratory

Using the benzalkon-crystal violet-ATP method (BC-ATP method), post-pasteurization contamination of pasteurized milk caused by gram-negative bacteria can be determined within 24 h. This study determined to what extent the keeping quality of pasteurized milk can be predicted by applying this BC-ATP method. Results obtained with the BC-ATP method for 100 samples of pasteurized milk were compared with those recorded in the shelf-life test (total bacterial count after 10 d of storage of samples at 7°C; standard: 106 bacteria per ml) and the Moseley test (bacterial count after 5 d of storage at 7°C; standard: 105 bacteria per ml). Using the shelf life test and the Moseley test, 14 and 8% of the results, respectively, did not correspond with those obtained with the BC-ATP method. From the results obtained, it was obvious that the greater the post-pasteurization contamination of the pasteurized milk, the lesser is the keeping quality. A quantitative estimation of the degree of post-pasteurization contamination can be obtained satisfactorily by applying the BC-ATP method to 1000-, 100-, 10- and 1-ml portions. The Moseley test takes too much time to achieve a good coordination between the factory laboratory and the pasteurization and filling sections of the dairy factory. By substituting the BC-ATP method applied to 100-ml portions of pasteurized milk for the Moseley test (5 d at 7°C; standard: 100,000 bacteria per ml) almost the same information is obtained within 24 h.

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 Keeping Quality of Milk and the Age on Testing for Total Bacterial Count

1931 ◽  
Vol 31 (3) ◽  
pp. 373-374 ◽  
Author(s):  
H. Barkworth
Keyword(s):  
Bacterial Count ◽  
Total Bacterial Count ◽  
Keeping Quality ◽  
Quality Of Milk

During the period 1923–29 inclusive nearly six thousand samples of milk were tested at Wye for both total bacterial count and also keeping quality. An examination of the results shows that on the average the afternoon milks showed nine hours less keeping quality than morning milks of the same total bacterial count, see Table I. The age of the milk on testing for total bacterial count (reckoned from the time of milking) is 27–29 hours for morning milks and 20–24 hours for afternoon milks.

A Membrane-Filter Technique to Test for the Significance of Sublethally Injured Bacteria in Retail Pasteurized Milk

1975 ◽  
Vol 38 (2) ◽  
pp. 87-88 ◽  
Author(s):  
T. J. CLAYDON
Keyword(s):  
Shelf Life ◽  
Membrane Filter ◽  
Selective Medium ◽  
Pasteurized Milk ◽  
Filter Technique ◽  
Litmus Milk ◽  
Keeping Quality ◽  
Membrane Transfer

A membrane transfer procedure previously described was used to study the possible role of sublethally injured bacteria in the keeping quality of retail pasteurized milk. Trypticase soy broth (TSB) was used as nonselective medium and TSB plus NaCl at pH 6.0 (TSBS 6.0), as the selective medium inhibitory to injured organisms. In pasteurized milk at early stages of storage, colony counts on the latter medium were much lower than on the former. Subsequent transfer of the TSBS 6.0 filters to fresh TSB and further incubation usually increased the counts to about the initial TSB range. Generally the organisms presumed injured and subsequently recovered were the same types as those considered uninjured. They were mainly streptococci and micrococci that produced only slow changes in litmus milk at 5 C, so they are of doubtful significance in the shelf life of retail milk at refrigerator temperatures.

scholarly journals EFFECTS OF PRESERVATIVE TREATMENTS ON THE MICROBIOLOGICAL AND STORAGE QUALITY OF TIGER NUT MILK DRINK

2021 ◽  
Vol 5 (11) ◽  
Author(s):  
Olofu A. Victor ◽  
Adeshina O. Gbonjubola ◽  
O. Busayo ◽  
Mshelia M. Bata
Keyword(s):  
Shelf Life ◽  
Standard Procedure ◽  
Bacterial Count ◽  
Total Coliform ◽  
Total Bacterial Count ◽  
Storage Quality ◽  
Microbial Stability ◽  
Total Fungi ◽  
And Storage

Tiger nut milk drink is a milk-like aqueous extract from tiger nut, which is highly nutritious and is consumed in most parts of the world especially in the Northern part of Nigeria. However, its availability is limited due to its short shelf life. The aim of this present study was to determine the effects of preservatives treatments on the microbiological and storage quality of tiger nut milk drink. Fresh tiger nut milk drink was produced according to the standard procedure with portable water and also with sterile distilled water. The milk was divided into 16 aliquots, kept in a sterile container for analysis of the different treatments, and preservatives were added according to the experimental design. The color, odor and consistency of the milk were observed daily for a period of seven days. The total bacteria count (TBC), total coliform count (TCC), total Staphylococcal count (TSC) and total fungi count (TFC) (yeast and mold) were evaluated every two days to monitor the microbial stability. Fresh tiger nut milk without any treatment spoiled within few hours after production, while the aliquot supplemented with all the preservatives; pasteurized and then stored under refrigerated temperature for up to seven days. The range of total bacterial count was from 8.00×104 -1.20×107 CFU/ml. The most prevalent bacterial isolates were; Escherichia coli (17.79%), Staphylococcus aureus (10.53%) and Micrococcus spp. (9.78%), whereas the dominant fungi were Candida tropicalis (16.27%), Saccharomyces spp. (11.63%) and Aspergillus spp. (11.63%). This study showed that tiger nut milk drink has a rich microbial content which affects its shelf life and the addition of natural (spices) and chemical preservatives is important to stabilize the drink; thus there is an urgent need to standardize the use of preservatives.

Effect of psychrotrophic post-pasteurization contamination on the keeping quality at 11 and 5 °C of HTST-pasteurized milk in the UK

1982 ◽  
Vol 49 (4) ◽  
pp. 619-630 ◽  
Author(s):  
Monika J. A. Schröder ◽  
Christina M. Cousins ◽  
Charles H. McKinnon
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Bacterial Counts ◽  
Pasteurized Milk ◽  
Colony Forming Units ◽  
Keeping Quality ◽  
The Uk ◽  
Spoilage Microflora

SummaryThe keeping quality of commercial HTST-pasteurized milk and laboratory pasteurized milk from a common bulk raw supply has been investigated for 5 dairies. Spoilage occurred at levels of total bacterial counts around 107 colony forming units/ml, but with a slightly higher off-flavour threshold for the commercial milks than the laboratory pasteurized milks. The predominant microflora at spoilage and the type of off-flavour produced differed between the 2 types of milk. Raising the storage temperature from 5 to 11 °C caused a slight shift in the spoilage microflora and led to an average reduction in the shelf life of the laboratory pasteurized milk from 28 to 6 d and of the commercial pasteurized milk from 13 to 5 d. Changes in the level of post-pasteurization contamination (PPC) were reflected in changes in keeping quality, particularly at 5 °C. However, the greatest improvements were found in the absence of PPC.

Effect of chia (Salvia hispanica L.) seeds incorporation on nutritional quality of muffin mix

2020 ◽  
Vol 50 (6) ◽  
pp. 1151-1161
Author(s):  
Vishakha Sharma ◽  
Renu Mogra ◽  
Azad Mordia
Keyword(s):  
Shelf Life ◽  
Wheat Flour ◽  
Control Sample ◽  
Value Added ◽  
Food Product ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Content Type ◽  
Salvia Hispanica L

Purpose Study on chia seeds is receiving increasing interest because of their nutritional and health-promoting properties that have been recognized by their high content of antioxidants, proteins, minerals and dietary fibers. Hence, the purpose of this study is to develop a value-added food product using chia seeds and to assess the nutritional properties, shelf life and consumer acceptability of the developed product. Design/methodology/approach Six different formulations of muffin mix were prepared by incorporating chia seeds with wheat flour in various ratios and evaluated for sensory characteristics. The nutritional components and shelf lives of the developed products were also evaluated. The developed product was stored for three months to assess the shelf life. Findings Results indicated that muffins made with chia seeds can be added up to 20% in wheat flour without affecting the sensory scores (p = 0.0014). Regarding nutritional evaluation, the results revealed that 20% incorporation of chia seeds significantly increased the total antioxidant activity (p = 0.001), increased the crude protein (p = 0.0001), fat (p = 0.0001) and crude fiber (p = 0.001) contents and lowered the carbohydrate (p = 0.0001) content when compared to the control sample. Muffin mix made with chia seeds had significantly higher mineral content (calcium, phosphorus, zinc and iron) than did the control. The developed product had a shelf-life stability of three months in terms of moisture content, peroxide value and total bacterial count and was well accepted by consumers. Originality/value Intrinsic characteristics of chia seeds can improve the quality of muffins and bring health benefits to the consumers.

PSYCHROPHILIC BACTERIA AND KEEPING QUALITY OF PASTEURIZED DAIRY PRODUCTSl1,2

1964 ◽  
Vol 27 (3) ◽  
pp. 69-75 ◽  
Author(s):  
P. R. Elliker ◽  
E. L. Sing ◽  
L. J. Christensen ◽  
W. E. Sandine
Keyword(s):  
Shelf Life ◽  
Bacterial Count ◽  
Economic Advantage ◽  
Sampling Techniques ◽  
Careful Study ◽  
Quality Test ◽  
Psychrophilic Bacteria ◽  
Keeping Quality ◽  
Plant Equipment

Summary A study was made showing relationship between post-pasteurization contamination of milk and cream and increase in bacterial count of bottled and paper carton products during storage at 45 F for 5 days. A survey indicated extensive post-pasteurization contamination in plants not employing this type of keeping quality test. The 5-day at 45 F test was more sensitive than the coliform test in detecting post pasteurization contamination. Excessive numbers of thermoduric bacteria in the raw supply also were detected by this method when plant equipment was properly cleaned and sanitized. Special in-line sampling techniques were developed to determine source of contamination. One procedure employed sterile disposable hypodermic syringes inserted through rubber stoppered nipples welded into lines at different locations in the system. Another technique involved removal of samples by insertion of sterile disposable hypodermic syringes through rubber or neoprene gaskets between joints in different locations in the plant. Bottle and paper carton filler equipment offered special cleaning and sanitizing problems and suggestions were made on steps to minimize contamination from these sources. Application of the 5-day at 45 F keeping quality test followed by careful study of contamination sources has greatly improved shelf life of pasteurized fluid milk and cream and has represented a real economic advantage to plants adopting the program.

Comparison between the EC plate count test at 21 °C and an accelerated plate count method for assessing the keeping quality of pasteurized milk

1992 ◽  
Vol 59 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Sarah A. Langford ◽  
Rohan G. Kroll
Keyword(s):  
Plate Count ◽  
Gram Negative ◽  
Rapid Methods ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Commercial Interest ◽  
Count Method ◽  
Keeping Quality ◽  
Plate Count Method

The keeping quality of properly refrigerated pasteurized milk and cream is primarily determined by post-pasteurization contamination by Gram-negative psychrotrophic bacteria (Phillips et al. 1981; Schröder et al. 1982). Reliable and rapid methods of assessing the levels of contamination by these organisms are therefore of commercial interest.

Effect of commercial probiotic (Protexin®) on growth, survival and microbial quality of shrimp (Litopenaeus vannamei)

2017 ◽  
Vol 47 (2) ◽  
pp. 204-216 ◽  
Author(s):  
Afshin Javadi ◽  
Seyed Amin Khatibi
Keyword(s):  
Survival Rate ◽  
Growth Performance ◽  
Litopenaeus Vannamei ◽  
Control Diet ◽  
Average Daily Gain ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Microbial Quality ◽  
Content Type

Purpose The purpose of this study was to investigate the effect of a dietary probiotic on the growth performance and survival rate of Litopenaeus vannamei shrimp. Furthermore, the microbial quality of shrimp was evaluated. Design/methodology/approach Shrimp were divided into treatment and control groups (each group containing 45 shrimp). They were fed for four weeks with a control diet alone or supplemented with a commercial probiotic (Protexin®). At the end of the trial, they were assessed for survival rate, weight gain, average daily gain and specific growth rate. Samples of tail meat were also provided aseptically from peeled shrimp for bacteriological analysis including the count of Staphylococcus aureus, enterococci, Clostridium perfringens, fecal coliform, Salmonella, Escherichia coli, Listeria monocytogenes and total bacterial count. Findings The growth performance of the probiotic-treated group significantly (p < 0.05) increased at the end of the experimental period. However, no significant differences were observed for the survival rate between the groups (p > 0.05). The count of C. perfringens and the total bacterial count in shrimp supplemented with the probiotic were significantly lower than those of controls (p < 0.05). The count of coliforms and S. aureus was not significantly different between the groups (p > 0.05). Originality/value It could be concluded that the probiotic bacteria have the potential to stimulate the growth performance of L. vannamei. They can also be used for biological control of food-borne pathogens and improve the microbial quality and safety of shrimp at the farm level.

Evaluating the presence of human pathogens in commercially frozen, biologically appropriate raw pet food sold in Italy

2020 ◽  
Vol 187 (7) ◽  
pp. e50-e50
Author(s):  
Benedetta Bottari ◽  
Elena Bancalari ◽  
Annalisa Barera ◽  
Sergio Ghidini ◽  
Monica Gatti
Keyword(s):  
Feeding Strategy ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Limit Set ◽  
Human Pathogens ◽  
Pet Food ◽  
Pet Owners ◽  
Larger Sample

BackgroundBiologically appropriate raw food (BARF) diet is becoming more and more popular among pet owners in Europe. However, there are documented microbiological risks associated with raw feeding, and this study aimed to determine the presence of human pathogens in commercially frozen BARF products sold in Italy.MethodsSalmonella species, Escherichia coli O157:H7, Listeria monocytogenes and Campylobacter species were identified. The general microbiological quality of BARF products and hygiene were also evaluated. Sample size was limited and therefore the study may not be representative of a larger sample.ResultsNone of the tested samples showed total bacterial count (TBC) higher than the limit set to consider a sample unacceptable. However, 14 out of 21 samples showed TBC higher than the limit set to consider a sample marginally acceptable. A high percentage of samples were contaminated by the aforementioned pathogens, highlighting the need for pet owners to be aware of the risks of this feeding strategy both to themselves and to their pets.ConclusionsConsidering that BARF diet meals can be prepared at home using the hands, as well as tools and spaces that could be shared, guidelines on safer handling of these pet food products should be recommended by veterinarians and nutritionists.

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