HACCP – analysis of dairy products – Part 3: Cheese

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Cheese production is one of the oldest processes for preserving perishable food drop which is milk, which spontaneously sours and coagulates.

Renneting begins with coagulation of casein and whey proteins. Casein can coagulate in the presence of acids up to pH = 4.6, which is the isoelectric point of casein. Whey proteins coagulate at temperature 90 to 95 ° C / 10-20 min.

During the cheese production process (selection and storage of milk, milk standardization, milk homogenization, milk heat treatment, curd cheese and cheese ripening) attention should be paid to the pH value and temperature of the product and the premises where production takes place.

When ripening cheeses, you should pay attention to the temperature because softer cheeses ripen at lower temperatures and shorter, while harder cheeses ripen at higher temperatures and longer.

When ripening cheeses with noble mold, for ripening with the growth of white mold, a temperature of 10-14 ° C and a relative humidity of 85-90% should be provided, among other conditions.

For ripening cheeses with blue mold, in addition to other conditions, a temperature of 10-13 ° C should be provided at a relative humidity of 90-95%.

The milk industry is a very complex technology with many critical points that need to be strictly controlled. And here are simple solutions to your problems from Hanna Instruments.

Portable Cheese pH Meter - HI99165

The Hanna Instruments HI99165 is a durable, waterproof, and portable Foodcare pH and temperature meter designed specifically for cheese analysis. Automatic calibration is performed at one or two points with two sets of buffers. All calibration and measurement readings are automatically compensated for temperature variations.

The HI99165 uses the FC2423 stainless steel body, amplified pH electrode that offers numerous features that improve pH testing for cheese producers. The split-level LCD displays both pH and temperature readings, along with indicators for reading stability, battery percentage, and calibration instructions.

Professional Portable Cheese pH Meter - HI98165

The HI98165 is a rugged, waterproof, portable Foodcare pH meter that measures pH and temperature using the specialized FC2423 cheese pH electrode. This professional, waterproof meter complies with IP67 standards. The HI98165 is supplied with all necessary accessories to perform a pH/temperature measurement packaged into a durable thermoformed carrying case that holds the meters, probes and calibration buffers securely in place.

Cheese products can provide a number of challenges for the person that needs to measure pH. Cheese products tend to be solid to semi-solids. Both types of samples will coat the sensitive glass membrane surface and/or clog the reference junction. The FC2423 that is supplied with the HI98165 is designed specifically for measuring pH in cheese. From a conic tip shape in a durable 5 mm diameter stainless steel body for easy penetration into cheese without leaving a large hole to an open junction that resist clogging; the FC2423 is an ideal general-purpose pH electrode for cheese. The FC2423 connects to the HI98165 with a quick-connect, waterproof DIN connector, allowing for a secure, non-threaded attachment.

Checktemp® 4 Folding Thermometer - HI151

The HI151 Checktemp® 4 is a folding thermistor thermometer that can measure temperature up to 300 °C (572 °F). These thermometers offer many advanced features including CAL-Check for an internal verification of the electronics and a motion sensor which eliminates the need of closing and reopening the probe when the meter enters a power saving mode. The Checktemp 4 is available in six different colors which can be assigned to different products to avoid cross contamination in the restaurant, kitchen or production facility.

HI700642P Cleaning Solution for Cheese Deposits (25 x 20 mL Sachets)

The HI700642P is a highly effective cleaning solution that is specially formulated for use with pH electrodes that become coated with cheese deposits. Electrodes can become dirty from use and will produce inaccurate results even as they read correctly in a pH buffer. Hanna’s cleaning solutions eliminate impurities and residues that are left on the electrode surface after taking measurements of cheese. Hanna suggests cleaning the bulb and junction of your electrode on a regular basis to ensure that the probe is always clean and prevent any clogging of the junction.

Each sachet has the lot number and expiration date stamped on it and is made of light block foil ensuring freshness each time one is opened. Hanna’s line of cleaning solutions have been specially formulated to have an expiration of 5 years from the date of manufacture for an unopened sachet.

Digital Refractometer for Measuring Sodium Chloride in Food - HI96821

The HI96821 is a rugged, portable digital refractometer designed for sodium chloride (NaCl) measurement. The HI96821 displays NaCl concentration four different ways: g/100 g, g/100 mL, specific gravity, and °Baume. The instrument’s high accuracy and simple operation gives reliable results each and every time. All readings are automatically compensated for temperature variations and displayed with a 1.5 second response time. The sealed flint glass prism and stainless steel well are easy to clean. Just wipe with a soft cloth in preparation for the next sample.

The HI96821 portable refractometer converts the refractive index of a food sample to g/100 g, g/100 mL, specific gravity and °Baume. These conversions are based on internationally recognized references for unit conversion. The HI96821 is ideal for the analysis of salad dressings, cheeses, condiments, canned and jarred foods, soups, brines and whey. The HI96821 is an easy to use tool for measuring sodium chloride in foods, whether on the production line or in the lab.

  • Designed for sodium chloride analysis in foods
  • Automatic Temperature Compensation
  • High accuracy measurements in g/100 g, g/100 mL, specific gravity and °Baume

Refractive Index

The HI96821 takes measurements based on a sample’s refractive index. Refractive index is a measurement of how light behaves as it passes through the sample. Depending on the sample’s composition, light will refract and reflect differently. By measuring this activity with a linear image sensor, the sample’s refractive index can be assessed and used to determine its physical properties such as concentration and density. In addition to the linear image sensor, the HI96821 uses an LED light, prism and lens to make measurement possible.

Variations in temperature will affect the accuracy of refractometry readings, so the use of temperature compensation is highly recommended for reliable results. The HI96821 contains a built-in temperature sensor and is programmed with temperature compensation algorithms in accordance with internationally recognized references which vary based on the parameter being measured.

Portable Thermohygrometer - HI9564

HI9564 is a portable thermohygrometer designed to provide peak performance in harsh environments. Measurements of temperature and relative humidity are made easy with the rugged, water-resistant housing of the meter and durable casing of the HI706023 probe. HI9564 features an auto-off function after 8 or 60 minutes, temperature readings in both Celsius and Fahrenheit, and on-screen messages to direct procedures and indicate potential errors. The HI9564 has selectable temperature and RH modes. The measurement mode can easily be switched at the press of the RANGE button. Both temperature and RH are measured with the HI706023 probe which features an internal temperature sensor and a built-in microchip that stores calibration data.

Author: Tajana Frančić, mag.nutr.