Agglutination Behavior of Lactic Streptococci

Scheuble, Todd L.; Kondo, Jeffery K.; Salih, Mohammed Ali

doi:10.3168/jds.s0022-0302(89)79211-0

Cited by 7 publications

(3 citation statements)

References 16 publications

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“…None of these methods have been reliable since measured agglutination titers did not correlate with severity of defects in cheese vats. Scheuble et al (1989) showed that only a small percentage of total immunoglobulins were actually involved in agglutination. Thus, we hypothesize that although agglutination titers may be an effective measure of the relative potential of a milk sample to cause agglutination, reaction intensities are probably related to the severity of agglutination associated with a particular strain.…”

Section: Discussionmentioning

confidence: 98%

“…Use of homogenized skim milk or milk pasteurized at higher than normal temperatures reduces agglutination (Emmons et al, 1966;Elliot and Emmons, 1979). Agglutination profiles also vary within the lactation cycle and titers differ among cows during the same stage of lactation (Emmons et al, 1966;Scheuble et al, 1989). It has been reported that protease-negative starter cultures have a higher frequency of agglutination problems in the cheese vat than their protease-positive counterparts (Milton et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

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Determining Lactococcal Agglutination by ELISA

Ustunol

Sypien

1996

Journal of Food Science

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An enzyme-linked immunosorbent assay (ELISA) was developed to determine the susceptibility of Lactococcus cultures to bind bovine milk IgM, IgG and IgA. Agglutination susceptible (agg + ) cultures bound high (PϽ0.05) concentrations of IgM, IgG and IgA, whereas agglutination resistant (agg Ϫ ) strains bound less. The agglutination variable (agg v ) cultures differed from the agglutination resistant (agg Ϫ ) cultures only in their ability to bind IgG. The ELISA was a reliable indicator of agglutination susceptibility for mixed as well as single strain cultures. Laser Scanning Microscopy (LSM) was used to verify results of ELISA. The IgG ELISA described here may provide a rapid, sensitive and a reliable method for identification and selection of agg Ϫ cultures.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Determining Lactococcal Agglutination by ELISA

Ustunol

Sypien

1996

Journal of Food Science

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“…Extent of agglutination depends on the cheese milk and strain of the lactic starter culture (Emmons et al, 1966;Jago and Swinbourne, 1954). Agglutination profiles also vary within the lactation cycle and titers differ among cows during the same stage of lactation (Emmons et al, 1966;Scheuble et al, 1989). Protease-negative starter cultures were reported to have a higher frequency of agglutination problems in the cheese vat than their protease-positive counterparts (Milton et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Heat Stability of Bovine Milk Immunoglobulins and Their Ability to Bind Lactococci as Determined by an ELISA

Ustunol

Sypien

1997

Journal of Food Science

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Immunoglobulins obtained from bovine colostrum were heat treated at 70, 75, 80 and 85°C for 0-90 min. An ELISA was developed to determine the susceptibility of lactococci to bind heat treated IgG, IgM and IgA. IgA was the most heat sensitive of the immunoglobulins. Treatment at 80°C for 25 min completely inactivated IgA as evidenced by the inability of lactococci to bind IgA. IgM was completely inactivated upon heating to 85°C for 20 min whereas IgG was completely inactivated at 85°C after 30 min. Laser Scanning Microscopy verified results with ELISA. Severe thermal treatment is needed to reduce immunogenicity of bovine milk to prevent lactococcal agglutination.

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Heavy coagulum formation in lactic casein manufacture: solids content, pH and gel strength variations through setting lactic coagulum

Weeks

Gosling

Munro

1994

Journal of Dairy Research

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Samples of lactic coagulum were obtained from various depths in a lactic casein silo. The casein content at the base of the silo was in the range 38-62 g/kg compared with 25-30 g/kg in the bulk of the silo. This layer of higher casein concentration, called heavy coagulum, was up to 1 m deep and appeared long before the bulk milk had fully coagulated. It had a lower pH than the bulk, e.g. pH 4-35 when the bulk pH was 5 -2. The heavy coagulum layer was removed from the silo last during pump-out. A laboratory coagulation tube was designed to permit more intensive study of heavy coagulum formation. Starter bacteria levels in the heavy coagulum were 10-160 times those in the bulk. Heavy coagulum had a visibly different curd structure (a much more granular gel), produced differently shaped extrusion curves, and had a higher gel strength than coagulum from the bulk. The heavy coagulum phenomenon had many similarities to minor sludge formation in Cottage cheese manufacture.The first step in the manufacture of lactic casein is the coagulation of skim milk in large silos by slow acidification with lactic starter bacteria (Southward & Walker, 1980). The coagulation stage is followed by cooking, acidulation, de-wheying, multiple stage washing with water, mechanical de-watering and thermal drying of the casein curd (Mulvihill, 1989).It has frequently been observed in the lactic casein industry that the last 3-5 % of the lactic coagulum pumped out of a silo into the process has a significantly higher gel strength and solids concentration than the bulk of the silo. This material of higher solids content is often referred to as heavy coagulum. This phenomenon has never been objectively studied, and is not well understood. For example, there has been debate as to whether the heavy coagulum initially forms on the base of the silo driven by gravity settling or at the top of the silo driven by flotation caused by gasproducing starters.A significant body of work has been published on an apparently similar phenomenon in Cottage cheese manufacture (Emmons et al. 1963(Emmons et al. , 1966Emmons & Elliott, 1967;Grandison et al. 1986a, b;Milton et al. 1990). Scheuble et al. (1989) indicate that a similar phenomenon may also occur in Cheddar cheese manufacture. Grandison et al. (1986a) separated the phenomena observed in Cottage cheese

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Agglutination Behavior of Lactic Streptococci

Cited by 7 publications

References 16 publications

Determining Lactococcal Agglutination by ELISA

Determining Lactococcal Agglutination by ELISA

Heat Stability of Bovine Milk Immunoglobulins and Their Ability to Bind Lactococci as Determined by an ELISA

Heavy coagulum formation in lactic casein manufacture: solids content, pH and gel strength variations through setting lactic coagulum

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