Effect of high pressure combined with mild heat or nisin on inoculated bacteria and mesophiles of goat's milk fresh cheese

2000 ◽  
Vol 17 (6) ◽  
pp. 633-641 ◽  
Author(s):  
M Capellas ◽  
M Mor-Mur ◽  
R Gervilla ◽  
J Yuste ◽  
B Guamis
1996 ◽  
Vol 59 (6) ◽  
pp. 582-587 ◽  
Author(s):  
MARTA CAPELLAS ◽  
MONTSERRAT MOR-MUR ◽  
ESTHER SENDRA ◽  
REYES PLA ◽  
BUENAVENTURA GUAMIS

Pasteurized goat's milk inoculated with Escherichia coli 405 CECT was manufactured into cheese containing 108CFU/g. The fresh cheese was treated by combinations of pressure (400, 450, and 500 MPa), temperature (2, 10, and 25°C) and time (5, 10, and 15 min). Once treated, cheeses were stored at 2 to 4°C. Counts of surviving Escherichia coli and aerobic mesophilic bacteria were determined 1, 15, 30, and 60 days after treatment. No colonies of surviving E. coli were detected 1 day after pressurization, except in samples treated for 5 min at 25°C at pressures of 400 and 450 MPa. No surviving E. coli were detected at 15, 30, or 60 days in any case. Aerobic mesophilic bacteria counts after treatment were between 2 and 3 log CFU/g in most cases and only a slight increase during refrigerated storage could be detected in samples treated at 400 MPa.


1998 ◽  
Vol 46 (7) ◽  
pp. 2523-2530 ◽  
Author(s):  
Andrew J. R. Law ◽  
Jeffrey Leaver ◽  
Xavier Felipe ◽  
Victoria Ferragut ◽  
Reyes Pla ◽  
...  

2019 ◽  
Vol 82 (9) ◽  
pp. 1553-1559 ◽  
Author(s):  
PALOMA QUINTANILLA ◽  
EVA DOMÉNECH ◽  
ISABEL ESCRICHE ◽  
M. CARMEN BELTRÁN ◽  
M. PILAR MOLINA

ABSTRACT Traces of antimicrobials in milk are of great concern for public health. The European Union has established maximum residue limits in milk; these, however, by themselves do not guarantee the absence of drug residues in milk and related products. Currently, very little information is available on the transfer of antibiotic residues from milk to other dairy products and their potential effect on food safety. This work evaluated the presence of antibiotic residues in pasteurized fluid milk and fresh cheeses from goat's milk containing these veterinary drugs at legal safety levels (maximum residue limits) and assessed the safety margin of these dairy products for consumers. Eight antibiotics (amoxicillin, benzylpenicillin, cloxacillin, neomycin, erythromycin, ciprofloxacin, enrofloxacin, and oxytetracycline) were selected, and three batches of fresh cheese were made from pasteurized goat's milk spiked with each of these drugs. Drug residues in milk and cheese samples were analyzed by liquid chromatography–tandem mass spectrometry. The safety margin of goat's milk products was calculated taking into account different age groups (children, teenagers, and adults). Results showed that most antibiotics present in raw milk remained in pasteurized milk and were transferred to cheese to a high extent; retention was above 50% in most cases. The minimum safety margin in pasteurized milk was obtained for enrofloxacin, ciprofloxacin, and erythromycin for the children's group. For fresh cheese, an elevated safety margin was obtained for all antibiotics and age groups considered. However, the large amounts of antibiotics retained in the cheese might contribute to the development and spread of antimicrobial resistance. Considering the differences in milk from different species and the great variety of cheeses, it would be advisable to continue the traceability study of antibiotics in order to increase the safety margin of dairy products.


2014 ◽  
Vol 77 (10) ◽  
pp. 1747-1753 ◽  
Author(s):  
J. P. DUBEY ◽  
S. K. VERMA ◽  
L. R. FERREIRA ◽  
S. OLIVEIRA ◽  
A. B. CASSINELLI ◽  
...  

The consumption of unpasteurized goat cheese and goat's milk has been suggested as a risk factor for toxoplasmosis in humans. In the present study, detection and survival of Toxoplasma gondii in milk and cheese was studied by bioassay in mice (milk) and in cats (cheese). Eight goats were inoculated orally with 300 to 10,000 oocysts of T. gondii strain TgGoatUS26. Milk samples were collected daily up to 30 days postinoculation and bioassayed in mice and cats. For mouse bioassay, 50 ml of milk samples were centrifuged, and the sediment was inoculated subcutaneously into mice. Mice were tested for T. gondii infection by seroconversion and by the demonstration of parasites. By mouse bioassay, T. gondii was detected in milk from all eight goats. The T. gondii excretion in milk was intermittent. For cat bioassay, 400 ml (100 ml or more from each goat) of milk from four goats from 6 to 27 days postinoculation were pooled daily, and cheese was made using rennin. Ten grams of cheese was fed daily to four cats, and cat feces were examined for oocyst shedding. One cat fed cheese shed oocysts 7 to 11 days after consuming cheese. Attempts were made to detect T. gondii DNA in milk of four goats; T. gondii was detected by PCR more consistently, but there was no correlation between detection of viable T. gondii by bioassay in mice and T. gondii DNA by PCR. Results indicate that T. gondii can be excreted in goat's milk and can survive in fresh cheese made by cold-enzyme treatment. To prevent transmission to humans or animals, milk should not be consumed raw. Raw fresh goat cheese made by cold-enzyme treatment of unpasteurized milk also should not be consumed.


2019 ◽  
Vol 43 (1) ◽  
pp. 50-58
Author(s):  
H. S. Alnaemi

     Fate of AflatoxinM1 in soft white cheese and its by-product (whey) and in yogurt locally made from raw sheep's and goat's milk experimentally inoculated with 0.05 and 0.5 µg/l AflatoxinM1 were investigated using ELISA technique. Results reported that AflatoxinM1 was concentrated in cheese at levels significantly higher than that recorded in the raw milk that used for its processing, with a significant decrease in AflatoxinM1 levels in its by-product (whey) comparable to the raw milk used in manufacturing at both inoculated levels. Yogurt produced from raw sheep's milk at second inoculated level exerted AflatoxinM1concentration significantly lower than that present in the milk. Significant differences in AflatoxinM1distribution in cheese and whey produced from sheep's milk comparable to their counterparts produced from goat's milk were recorded. Finally, results revealed the efficacious role of the various dairy manufacturing processes in AflatoxinM1 distribution and the necessity to issue of local legislations concerning the maximum permissible limits for AflatoxinM1 in milk in order to stay within the universal permissible levels for AflatoxinM1 in dairy products to provide greater protection for consumer health. 


2021 ◽  
pp. 108201322110037
Author(s):  
Ercan Sarica ◽  
Hayri Coşkun

This study was aimed to determine the changes in kefir samples (CK and GK) made from cow’s and goat’s milk during frozen storage. The CK and GK samples were first stored at +4 °C for 14 and 21 days. Thereafter, all the samples were frozen at –35 °C for 24 h and kept at –18 °C for 45 days. There was no significant change in the fat, protein, acidity and pH values in both samples during the storage. The values of viscosity, WI and C* were higher in the CK samples while the syneresis value was higher in the GK samples throughout the frozen storage. The microorganisms ( Lactococcus spp., Lactobacillus spp., Leuconostoc spp., total mesophilic aerobic bacteria and yeasts) found in kefir made from goat's milk were more affected from the frozen storage. In both samples, the changes in organic acids and volatile flavor components were not significant during frozen storage, except acetic, citric and oxalic acids and acetaldehyde in GK sample. In addition, CK samples were preferred sensorially more by the panellists during frozen storage.


Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2625
Author(s):  
Muzammeer Mansor ◽  
Jameel R. Al-Obaidi ◽  
Nurain Nadiah Jaafar ◽  
Intan Hakimah Ismail ◽  
Atiqah Farah Zakaria ◽  
...  

Two-dimensional electrophoretic (2DE)-based proteomics remains a powerful tool for allergenomic analysis of goat’s milk but requires effective extraction of proteins to accurately profile the overall causative allergens. However, there are several current issues with goat’s milk allergenomic analysis, and among these are the absence of established standardized extraction method for goat’s milk proteomes and the complexity of goat’s milk matrix that may hamper the efficacy of protein extraction. This study aimed to evaluate the efficacies of three different protein extraction methods, qualitatively and quantitatively, for the 2DE-proteomics, using milk from two commercial dairy goats in Malaysia, Saanen, and Jamnapari. Goat’s milk samples from both breeds were extracted by using three different methods: a milk dilution in urea/thiourea based buffer (Method A), a triphasic separation protocol in methanol/chloroform solution (Method B), and a dilution in sulfite-based buffer (Method C). The efficacies of the extraction methods were assessed further by performing the protein concentration assay and 1D and 2D SDS-PAGE profiling, as well as identifying proteins by MALDI-TOF/TOF MS/MS. The results showed that method A recovered the highest amount of proteins (72.68% for Saanen and 71.25% for Jamnapari) and produced the highest number of protein spots (199 ± 16.1 and 267 ± 10.6 total spots for Saanen and Jamnapari, respectively) with superior gel resolution and minimal streaking. Six milk protein spots from both breeds were identified based on the positive peptide mass fingerprinting matches with ruminant milk proteins from public databases, using the Mascot software. These results attest to the fitness of the optimized protein extraction protocol, method A, for 2DE proteomic and future allergenomic analysis of the goat’s milk.


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